Friday, February 15, 2013

Flying the Caravelle

Back in the sixties when airliner watching was a real down to earth pleasure. I use to listen for the high pitch sound of the Rolls Royce engines high in the sky coming from a United Airlines Caravelle flying along J-60 going into New York. It was always a pleasure to see the caravelle letting down over my home town. Airliner watching was a great hobby.
Found this article in the 1957 edition of Flight Global.
Flying the Caravelle

France's First Jet Airliner
THE first jet airliner to emerge from the French aircraft industry as a complete commercial project is the S.E.210 Caravelle. The prototype, F-WHHH, was rolled out on April 21st and is now undergoing a thorough ground-check, including engine runs and taxying trials. It is expected to make its first flight in the very near future. Work started in February 1953, when metal was first cut and actual assembly began one month later when the first pieces arrived at the S.E. experimental hangar at Toulouse-Blagnac. The project was originally proposed in November 1951 when the Service Technique of the French Government, the Ministry of Transport and several aircraft companies met to formulate a specification. The requirement was for a new medium-range transport with an all-up weight of 35 to 40 tonnes (77,000 to 88,000 lb) powered by any French turbojet then available. Besides the Caravelle, five other projects were formulated and submitted, but for one reason or another all but the Caravelle were eventually dropped. S.N.C.A.S.O. and Breguet designs were not proceeded with; a Latecoere design required by-pass turbojets, but none was then available; a S.N.C.A.N. design was held up for a similar reason; and the Hurel Dubois 45 was initially accepted. S.E. decided to use the Atar, which was then able to deliver 2300 kg (6,170 lb) thrust, but this required the use of three engines; so extensive studies were made to find a suitable power plant layout. Since the third engine would obviously have to be installed on the centre-line, the tail suggested itself and it appeared that there was much to be gained from grouping all three engines there. Wind-tunnel tests showed that the problems of such an unusual arrangement were far less than might be expected and that there were even a number of very significant advantages. The wing would be clear of all aerodynamic and structural interference from the engines (either podded or buried) and the flaps would likewise benefit. Since all fuel would logically be held in the wing, the fire risks would be greatly reduced by the separation of tanks from engines. Noise levels in the cabin also promised to be exceptionally low. The change of intake angle of attack with wing angle of attack for engines mounted in the tail is half that for engines mounted in pods under the wing and fuselage. In the event of wheels-up landing, the fire risk would be small, due to the wide separation of engines and tankage, and also because the engines would not touch the ground. The asymmetric power case would also be simpler, and the company claims that full thrust from one engine only at take-off can be held with 6 deg of rudder. By April 1952 the project had been finalized and detail design began on the Caravelle and on the Hurel Dubois H.D.45 high- aspect-ratio jet transport. This latter design now appears to have been dropped, leaving the Caravelle alone in the field. In 1952 it became apparent that engines of considerably greater power than the original Atar would be available in time for
incorporation in the Caravelle. The company therefore decided to make use of what seemed likely to become one of the standard NATO power plants, namely a late mark of Rolls-Royce Avon. The thrust which could be expected was 4,200 kg (9,260 Ib) and two of these engines would give as much power as the three originally considered. No change in the basic layout was made and Avon RA. 26s were eventually chosen. It might be argued that if three RA. 26s had been installed the Caravelle's perform- ance and range would have been greatly increased, but this, the company claims, would bring the Caravelle into direct rivalry with the Comet 3; there is no intention of taking this course, or of going beyond the original specification for a medium-range transport. At the beginning the S.E.210 was to be called Annapurna, but early in its history this name was changed to Caravelle and has remained so since. At the time of Flight's visit to Toulouse it was intended that the Caravelle should be demonstrated in flight at the Paris Salon in June and the test schedule has been arranged so that the necessary ten hours' flying will be completed in time for the show. There are at the moment no firm orders for the Caravelle, but construction and tooling are being planned for a probable run of 50 aircraft. With this in mind, the second prototype is scheduled to fly 10 months after the first, and the first production aircraft could be ready for delivery in January 1958. Constructors' flight trials should take 500 hours, followed by a period of tests by pilots and technicians of the Centre d'Essais en Vol. After that an operator (and there is a strong feeling that it will be Air France) will carry out a further 1,000 hours of range, endurance and pro/ing flights. Despite the fact that there are no orders yet, it is noteworthy that Air France has taken a constructive part in the Caravelle project since its beginnings. An electrical expert, a structural engineer and a pilot have been attached to the company for some time past in an advisory capacity, and co-operation between the two organizations has been close and continuous. The participation of a commercial operator in the design from such early stages gives promise of an excellent result. Even in the partly clothed skeleton of the aircraft many points could be noted which showed careful thought and ingenious design. The control system, in particular, gave the appearance of being a real "copy book" layout. The design of a jet airliner, particularly in view of the events of last year, would appear to be a difficult task indeed. When many of the critical sections of the Caravelle were in the design stage, less was known about the behaviour of such parts in service than is now the case. S.E. have, however, been able to benefit in this respect from a close liaison with de Havilland's in England, and a number of features of the CaraveUe have been prepared in the light of the English company's experience. The question which particularly came to mind when Flight visited Toulouse was that of the qualities of the pressure cabin and the strength of the windows and cut-outs. Naturally the now customary tank-tests were mentioned. S.E. had, of course, already 

carried out a full range of strength tests on windows and other cut-outs and on sections of the fuselage itself. As soon as a complete fuselage and wings become available for this purpose, tank tests will also be made. For the tank itself, incidentally, the company is relying on what they term extensive British war-time experience in the making of prefabricated water tanks. This item, therefore, is not regarded as a major construction problem, and can be built easily enough when the ti!ne comes. The first prototype will not be furnished, but will naturally fly pressurized in due course. It will differ structurally from production aircraft mainly in having an escape chute in the cabin floor. The chute is arranged to pass through a hatch in the cabin floor immediately above the normal forward under-fuselage baggage hatch, so that its presence does not materially affect the fuselage structure. The other major variation is in the leading edge. At present a "droop-snoot" is fitted, but produc- tion aircraft will have permanently drooped leading-edges, and extensive research has been carried out to find the optimum droop angle. The team responsible for the Caravelle was, until some months ago, led by M. Pierre Satre, but he has suffered ill health and his duties have been taken over by M. Etienne Escola, head of the design department. M. Georges Favereau is in charge of production and the liaison between the two departments is assured by M. R. Douat. In charge of subsections are M. Paul Vallat, fuselage, M. de Lamaze, wings, M. J. Lepers, equipment, M. J. Frustie, installations, and M. Jean Muron, controls. The objective throughout the design of the Caravelle has been to produce a medium-range jet airliner capable of operating from existing air- fields in France and her African possessions, and in Europe in general. Particular care has been taken to make the Caravelle if anything less de- pendent on ground facilities than equivalent piston-engined aircraft. The internal batteries are designed for use in engine starting without outside assistance; and the passenger stairs, which can be lowered by hydraulic jack from under the tail, should contribute to easy access, while also acting as a stern prop. The Caravelle is intended as an alternative passenger, freight or mixed cargo aircraft, and to that end a large, hydraulically operated freight door is provided forward of the wing and to port. All systems have been designed to operate almost automatically, yet with full detailed control available in case of failure of any section.
It is intended, at least in principle, that the flight crew should be two pilots only, but here the designers are up against the stated resolve of the airline pilots not to work two-man crews, and allowance is therefore made for a flight-crew of three. Caravelle production is to be undertaken jointly by S.N.C.A.S.E. and S.N.C.A.S.O., with the latter company making the wings and the former in charge of assembly. The first cost of a Caravelle is estimated at 425 million francs (£439,000 approximately). The company is not prepared to make any estimate of operating cost, because of the great variety of conditions which influence such estimates. There are, however, a number of factors which will make for low costs—particularly the twin-engined layout, which decreases the fuel, maintenance and spares expenses. The crew is, moreover, small; it would normally consist of four, either two piiots and two stewards, or three flight crew and one steward. The turn-round has been specially studied and simplified, particularly in regard to the equipment required. An important profit-making consideration is that maximum use should be made on all flights of the aircraft's freight capacity, and S.E. point out that, since the whole fuselage floor is strengthened for freight, the full payload can always be made up in this way. The volu- metric capacity is equal to that of a DC-6. Cockpit layout has been carefully prepared and, in so far as
the basic systems are concerned, is virtually finalized. Radio installations and interior furnishing of the cabin are, however, being left entirely to the operator. A suggested radio installation would include Standard Telephones and Cables STR 18B H.F./R.T. and STR 12D V.H.F.; American Sperry C2A gyro- compass (its English Sperry equivalent was described in Flight on April 2nd, 1954); Lear L-5 autopilot (of which develop- ments were described in Flight, February 18th); Marconi AD 7092D Radio-magnetic Indicator; Collins 51 R3 V.O.R. and I.L.S. localizer receiver and 51V2 glide-path receiver; Bendix MN 53B marker beacon receiver. All this equipment would naturally be duplicated. •
Structure: Fuselage
The fuselage is a stressed skin structure 103ft 4in long, including a cylindrical section of 51ft 8in with a diameter of 12ft 6in. The pressurized section measures 83ft 6in and has a volume of 6,003.8 cu ft. The passenger/freight cabin is 44ft 4in long, with a floor area of 430.5 sq ft and a maximum height of 6ft 8in. There are 28 windows, 11 of which are inward-opening escape hatches. Normal accommodation is for 70 passengers seated five abreast, but a high-density version could hold 91. There are two under- floor freight compartments, one measuring 21ft 4in by 2ft 3in, the other 18ft by 2ft; their combined capacity is 434.3 cu ft. In addition, there is baggage space forward of and behind the pas- senger cabin. Entry is by retractable stairway under the tail with an inward-opening door through the flat rear pressure-bulkhead, and freight can be loaded, without interfering with routine turn- round operations, through a freight hatch, measuring 6ft 6in by 5ft llin high, on the port side of the forward fuselage. A small sliding door is inset. There are 75 frames in the fuselage, of which 15 are reinforced. No. 7 marks the junction, immediately behind the windscreen, of the Comet nose-section with the S.E. fuselage. No. 13 picks up the nosewheel mounting and marks the forward edge of the freight door, whose rear edge is reinforced by frame 19. Nos. 31, 35 and 41 mark the wing/fuselage pick-up and Nos. 48, 51, 53 and 56 are frames braced by square-tube girders for engine and nacelle mountings. No. 60 is the flat cabin rear bulkhead, and Nos. 63, 65 and 69 pick up the spars of the fin. No. 73 marks the beginning of the tail-cone and holds the tunnel for the 22.4ft ribbon tail-braking parachute. The fuselage is built in three sections: nose, tail-cone, and cylindrical centre section. The nose is built on a vertical jig, from stringers pre-shaped on a rotatable plaster forme, and with pre- formed skin sections. For production aircraft, these will be stretch-formed. The fuselage centre section is built up of a number of smaller components assembled in the main fuselage jig. The actual engine-mountings depend from frames 53 and 56, from which bridge structures pass over the top of the engines to pick up the mounting points. This leaves the lower half of the engine cowling structure free of main supports, and the forward section hinges downwards on its outer edge to provide access for servicing. The rearward portion under the tail-pipe is detachable by means of quick releases. The rear pressure bulkhead is located level with the engine effluxes and consists of two diaphragms heavily reinforced with radial webs to the rectangular door frame. The forward face holds cabin pressure and the rear face is liberally perforated with flanged lightening holes. On this rear face are mounted the blue and green hydraulic reservoirs; and on the sloping tunnel, which accommodates the steps when retracted, are mounted the heat-exchangers with their rectangular ducts leading downwards from the fin-root intakes. The main rudder hinge (and the beam, on which the rudder Servodyne is supported) depends from rib 69, which is reinforced by a built-up web structure. At continuous level, the cabin floor is built up on transverse beams integral with each frame, supported by tube struts or, in areas of stress concentration, by square-tube girders. Two A.D.F. serial compartments are buried in the roof of the forward cylindrical fuselage section.
the level of the tailplane as an integral part of the fuselage between the reinforced frames 63 and 69. Forward of this the dorsal fin is added. To the top of this structure the tailplane, built in one piece, is bolted and on top of this again is the main fin. It is a two-spar structure built up as a torsion-box of lattice ribs, three of which carry rudder hinge-brackets built out from the rear spar inside a simple shroud structure. The rudder itself is horn- balanced and the hinges are not inset. The tailplane has a span of 34ft 9in and an area of 301.4 sq ft. In order to achieve good control at high speeds, it has a greater sweep (30 deg at 25 per cent chord) than the wing and a smaller thickness /chord ratio. Like that of the fin, its aerofoil section is N.A.C.A. 65011. The elevator area is 69.42 sq ft. The tailplane structure is very similar to that of the wing, consisting of a pre-formed skin with span-wise stringers (here spot-welded), on which double-crescent-shaped ribs inboard and simple profile ribs outboard are assembled in a jig. The two halves, upper and lower, are then joined together to form the torsion-box. Forward of this, the detachable leading-edge section with its hot air ducts is added and the elevator hinges are built out on extended ribs and masked by simple reinforced-sheet, tube- braced shrouds. The elevator itself is a single spar structure with a modified form of crescent half-rib construction inboard and plain ribs outboard. A series of mass-balanced weights are cantilevered out from the elevator spar within the shroud hinge compartment. It is on top of the central carry-through section of the tailplane that the elevator Servodyne is mounted.
Performance The company were not prepared to give more than the briefest estimate of aircraft performance before the prototype had flown. According to calculations, however, the structural Mach limit of the Caravelle is 0.87, and the stalling speed at maximum landing weight in the landing configuration is 87 kt. Estimates of runway length required and payload/range have been subject to variation as improved versions of the Avon became available. The company's brochure gives two sets of performance graphs based on a thrust of 10,000 lb and 11,000 lb from each engine, and we quote here the figures for an engine of 11,000 1b static thrust. In addition, S.E.'s calculation of engine
performance in hot air proved somewhat conservative and, accord- ing to the latest figures from Rolls-Royce, the take-off weight graphs have been modified. The curves for the latest estimates are shown in the accompanying graphs. Cruising speed is estimated as 480 m.p.h. at 36,000ft and at a flying weight of 77,000 lb. In the light of modern design methods, the systems in an aircraft are of major importance. Especially is this so in the case of the Caravelle, whose controls are entirely hydraulically operated.

TO get the Caravelle moving in order to taxi out it is necessary to use the two Rolls-Royce Avon RA.29s at about 60 per cent power; they are first opened up to 5,000 r.p.m., and the correct taxying speed can thereafter be maintained with about 4,500 r.p.m. Directional control is by the steerable nosewheel, making use of brakes unnecessary; owing to the fact that the engines lie so close to the fuselage centre-line asymmetric power is not practicable for steering HERE is "Flight's" first report of the flying characteristics of the Sud Aviation Caravelle, France's increasingly favoured short-range jet air- liner—a class of aeroplane which is commanding the close attention of the British industry at the present time.

The author, who regularly contributes Italian news to our pages, is also a free-lance test pilot. purposes. Rudder control becomes effective at 75 to 80 kt. Full take-off power—10,500 lb thrust at 8,160 r.p.m.—can be held on the brakes. For take-off the best flap setting is 10 deg. Allowable eg. travel is between 20 per cent and 35 per cent of the mean aerodynamic chord. With the Caravelle at a gross weight of 90,400 lb the nosewheel is brought off at about 7 kt below unsticking speed, which is 120 kt. Longitudinal stability, both during and after take-off, seemed good. Forward visibility I found to be beyond criticism, but on this prototype the outlook to each side—and especially to starboard—left something to be desired; improvements are promised in the production version. From "brakes off" the full-weight take-off run lasts approxi- mately 30 sec at an ambient temperature of about 20 deg C, and the undercarriage and flaps can be brought fully up some 20 sec after leaving the runway. Optimum climbing speed— 255 kt—is attained in 55 sec. The time taken to reach safety speed of 1.3 V8 hardly calls for consideration, as the Caravelle does not normally unstick until this speed has been passed. In accordance with American C.A.R.4b requirements, for take-off at an airport altitude of 3,280ft a gross-weight reduc- tion of 5,500 lb is necessary in order to achieve a take-off dis- tance comparable with the full-weight sea-level figure. An increase of 10 deg C in airport temperature implies a weight reduction of about 2,600 lb. To put the matter another way: for operations at maximum weight these airfield conditions require, respectively, a 9 per cent increase in take-off distance in the first case and a 490ft increase in the second.

One increases optimum climbing speed progressively to 290 kt at 13,000ft, thereafter holding it at that figure up to cruising levels. Engine r.p.m. are held at 7,100 up to 30,000ft, then increased slightly (to 7,250) until the desired cruise alti- tude is attained. Initial rate of climb is about l,500ft/min (with a jet-pipe temperature of 580 deg C) and service ceiling is in the region of 42,000ft. Spiral stability is positive in both cruising and approach configurations. In approach and landing configuration the unaccelerated stalling speed at gross weight is about 90 kt, and one finds that a slight tendency to drop a wing can be easily counteracted by use of aileron. At all altitudes, and with any e.g. position, a slight reversal of stick forces occurs at approximately 100 kt. This is not caused by instability, but by airflow changes, and an automatic trimming device now counteracts it, so that the pilot is not aware of the effect. The trimmer is capable of cancelling-out stick forces at any e.g. position and airspeed. Trimming is accomplished by varying the datum position of the jack which applies artificial-feel loads to the control column. The control system [described in detail in Flight for May 27, 1955] is fully powered, with two independent hydraulic supplies; there is no means of reversion to manual control. Asymmetric power produces no yaw, because the thrust lines pass through the e.g., and no trimming is required to counteract yawing or rolling moments. By using the sensitive and effective trimmer it can be established that the Caravelle is longitudinally statically stable in all configurations and e.g. positions. A standard climb to 33,000ft covers 220 miles, takes 40 min and uses 4,400 lb of kerosine. Between 33,000 and 38,000ft, cruising speed at 7,250 r.p.m. settles at 390 kt with a fuel con- sumption of 4,400 lb/hr. At 32,000ft, cruising speed is 400 kt and fuel consumption 5,000 lb/hr. Maximum level speed at 20,000ft is 270 kt I.A.S.; and in this condition dynamic stability remains good, even with acceleration from 1.5 to 2 g. Decreased temperatures at the higher altitudes cause a slight control friction, but effectiveness is not lost and the stick continues to return to neutral even after being sharply dis- placed.

 The layout of the air-conditioning and pressurization system was described in detail in Flight for May 27, 1955. In practice one finds that the indicators and controls are well positioned and the system as a whole effective. Sea-level cabin pressure can be held up to 18,000ft, which allows the maximum rate of descent of 5,800ft/min to be used without causing discomfort to the passengers. A standard demand- regulator oxygen system is fitted for the crew; and the "blinker" indicators are well placed for easy observation when necessary. Pressurization, air-conditioning, anti-icing and fuel system are controlled from panels distributed around the co-pilot's seat. The highest Mach number reached during my test was 0.84 at between 35,000 and 40,000ft. The only compressibility effect was a slight buffeting which began at a Mach number of 0.82; and there were no pitching tendencies other than those caused by the normal changes in static stability follow- ing increase in speed. Airbrakes, which may be used at maximum Mach number and I.A.S., extend in three seconds but cause a certain amount of vibration. Reduction of power is also an effective way of reducing speed. Aileron effective- ness is maintained at all speeds and Mach numbers. A typical let-down from 38,000ft to 5,000ft is made without airbrakes at a constant 216 kt in 36 min, covering 150 miles and using 660 lb of fuel. Standard reserves permit 45 min holding at 10,000ft, a missed approach and a diversion of 150 miles, using 6,600 1b of fuel. During the approach and landing one finds that flap and undercarriage extension cause negligible trim changes, and the airbrakes remain very effective. The normal approach is made with power at 1.5VSL (135 kt). Small power-variations produce only small results, but a strongish ground effect in calm conditions distinctly assists the pilot in rounding out. In power-off approaches or strong winds this effect dis- appears. From the 4,500 r.p.m. approach setting, full power can be reached in five seconds and acceleration is then suffi- cient to re-establish safety speed very rapidly. With the tail braking parachute the landing run can be limited to 1,800ft; without it, at a weight of 86,000 lb and in standard atmos- phere, the ground run is 2,160ft. At 66,000 lb the run is reduced by 650ft. [A full structural description of the Caravelle, with cutaway drawing, first appeared in Flight for May 20, 1955.



Monday, December 10, 2012

The Airport (1948)

Remember when flying was this easy....Chalk Boards, Handing the pilot a load manifest with a long pole....Great! Wgeb life was easy and simple.

Thursday, May 24, 2012






 Crew: 3 or  
Capacity: 40
                  Length: 74 ft 7 in (22.73 m)                   
Wingspan: 93 ft 3 in (28.42 m)
                   Height: 28 ft 5 in (8.66 m)
                    Wing area: 864 ft2 (80.27 m2)
                    Empty weight: 29,126 lb (13,211 kg)
                    Gross weight: 44,900 lb (20,366 kg)
                   Powerplant: 2 × Pratt & Whitney R-2800-CB16 radial piston engine, 2,400 hp (1,790 kW) each
                    Maximum speed: 312 mph (502 km/h)
                    Range: 1,080 miles (1,783 km)
                    Service ceiling: 29,000 ft (8,840 m)

First deliveries in 1951 were made to Eastern Air Lines (EAL) who had ordered 60

EAL operated their 4-0-4s in the eastern USA using the class name "Silver Falcon". The first EAL schedule was flown on 5 January 1952 and retirement came in late 1962.


PRATT AND WHITNEY R-2800 CB16 radial piston engine, 2,400 hp





















Wednesday, May 9, 2012

A Strange Aircraft...The Custer Channel Wing

This is a little walk around of the Custer Channel Wing, sitting on the ramp at Mid Atlantic Air Museum at the Reading Pa. Airport.

The channel wing is an aircraft wing principle developed by Willard Ray Custer in the 1920s. The most important part of the wing consists of a half-tube with an engine placed in the middle, driving a propeller placed at the rear end of the channel formed by the half-tube.
A wing functions because the air over the wing has a lower pressure than the air under it. The conventional aircraft must reach a significant minimum speed before this pressure differential become large enough that it generates sufficient lift to become airborne.
In Custer's channel wing the rotating propeller will direct a stable stream of air backwards through the channel. A propeller will at the low pressure side normally be supplied by air from all directions. Since the half-tube prevents air from being drawn from below, the air will be sucked through the channel instead. This creates a strong low pressure area in the channel, which again generates a lift.

The old bird is in rough shape. 

looking head on


No. 2 and right side

Cockpit Throttle Pedestal

No2 aft

No. 1 aft

Check out the Custer Channel Wing Web Site:

Monday, August 29, 2011


PAN AM B-377

On January 15, 2009 U.S.Air Flight 1549 a regulary scheduled flight from Laguardia Airport in New York to to Charlotte/Douglas International Airport, Charlotte, North Carolina. was successfully ditched in the Hudson River adjacent to midtown Manhattan six minutes after takeoff from LaGuardia Airport after being disabled by striking a flock of Canada Geese during its initial climb out. The incident became known as the "Miracle on the Hudson.

I totally agree that Flight 1547 and Captain Sullenberger's successful ditching was indeed one of the most interesting and successful ditching of an airliner. But for me, the most amazing and intricate ditching occurred 55 years ago on October 16, 1956. With the ditching in the Pacific Ocean of Pan Am Clipper Flight 6, a Boeing 377 Stratocruiser owned and operated by Pan American World Airways and piloted by one of my aviation heroes Captain Richard N. Ogg. Described by Life Magazine writer Herbert Brean as A tall, reticent thoughtful man.

Concerning Captain Ogg, this article was written by Scott Herhold of the Mercury News
The miracle on the Hudson had a local precedent

Richard N. Ogg, a Pan-Am pilot who lived in Saratoga, brought a... (Mercury News archives)
The pilot remembered a "very heavy" impact when the plane hit the water after losing two engines. He praised the passengers for staying calm as they filed out into the three life rafts. When he was acclaimed for rescuing everyone aboard, he was fixedly modest: "To me, it was just a matter of doing my job,'' he said

Chesley B. "Sully'' Sullenberger, the man who landed US Airways Flight 1549 on the Hudson River? No: The hero 52 years ago was Richard N. Ogg, a veteran pilot from Saratoga who landed a Pan American Stratocruiser on the Pacific Ocean, saving all 31 aboard. The miracle on the Hudson had a precedent.
Forever after, his superb ditching defined Ogg's career: He regularly spoke before aviation groups about safety procedures. Once, when he had a faraway look on his face, his wife, Margaret, asked him what he was thinking. Ogg answered that he was pondering the fate of a group of canaries that drowned in the hold when the plane went down.

Peril over the Pacific Ogg, then 42, had been a pilot for two decades when he took off from Honolulu at 9:30 p.m. on Sunday, Oct. 14, 1956, bound for San Francisco with 24 passengers and six other crew members. The name of his craft was "Sovereign of the Skies," but that night, it had to depend on others to survive.

The pilot later told San Jose Kiwanis Club members that he had completed the first leg of his trip when his number one engine, on the far left-hand side, failed. Ogg tried to feather the propeller, or alter the pitch of the blades, but it continued to "windmill," putting a tremendous drag on the plane. With the number four engine also malfunctioning and his air speed reduced to 140 knots, Ogg knew he would probably have to ditch.

Luck was with him: Ten minutes before, he had passed a Coast Guard cutter, the Pontchartrain. Ogg turned the heavy Stratocruiser around and began five hours of circling the Pontchartrain, waiting for daylight and for his tanks to empty of fuel. He practiced ditching at least three times.

At 8:16 a.m. Pacific Standard Time —7:16 a.m. by the Pontchartrain's clock — Ogg brought the Stratocruiser down in 5-foot swells and an 8-knot wind. He knew the tail would probably crack up, and it did. "We hit with a good bump but we knew we would be all right," said the 6-foot-4 captain.

Miraculously, everyone on board was rescued within five minutes, although a few passengers fell into the water as they departed the plane. Only five people reported minor injuries.
A hero's welcome
When he came back to San Francisco and to his home on Winter Lane in Saratoga, Ogg was given a hero's welcome, just as Sullenberger was in Danville last weekend. There was one obvious difference: With fewer lawyers to bring lawsuits, Ogg spoke freely of the ditching. Sullenberger has avoided releasing details in public.

A loyal Pan-Am pilot, Ogg stayed with the faltering airline until he retired in 1971, not long before it went bankrupt. He continued to fly privately for almost two decades afterward, frequently taking his single-wing Mooney aircraft to his home state of Montana.
Before Ogg died of colon cancer in 1991, Margaret once asked him whether he had ever been afraid. "When I went in for open-heart surgery," Ogg responded. What about the ditching? she asked. "Oh, I was just so busy trying to remember everything I learned that I didn't have time," he said.

Below is my story of Clipper Flight 6 amd the amazing ditching.

Editors Note: All flight data and information was taken from the official CAB Accident Investigation Report Released on July 11, 1957.
Times are all Hawaii Standard Time. Actuall times may differ by 2 or 3 minutes.
I also took the personal info from a story written by Herbert Brean Froim Vol. 41 No. 18 October 29, 1956 issue.

In memory of Captain Richard N. Ogg and the flight crew of Clipper flight 6.

The ditching of Pan American Boeing 377, N90943 October 16, 1956.

Pan Am flight 6 was a regularly scheduled around-the-world flight eastbound from Philadelphia, Pennsylvania. to San Francisco, California. with en route stops in Europe, Asia. and various Pacific Islands. All prior segments had been routine and the flight departed Honolulu on the last leg of the -trip on October 15.
The last leg of this around the world flight was from Honolulu to San Francisco was being flown by a veteran Pan Am crew led by:

Captain Richard N. Ogg, age 43, was employed by Pan American World Airways on February 20, 194L. He held a valid airman certificate with airline transport rating and rating for the subject aircraft. Captain Ogg had a total of 13,089:41 flying hours., of which 738:27 were in Boeing 377s. He had passed a CAA medical examination m September 21, 1956. He had completed an emergency equipment training course dry ditching - on June 4., 1956.

First Officer George L. Haaker, age 40, was employed by PAWA on March 1, 1946. He held a valid airman certificate with airline transport rating and rating for the subject aircraft. Mr. Haaker had a total of 7,576.00 flying hours, of which 3.674:06 were in Boeing 377's. His last physical examination was passed m September 4, 1956. He completed an emergency ditching training course on August 2, 1956.

Flight Engineer Frank Garcia, Jr., age 30, was employed by PAWA on August 16, 1954. He held a valid flight engineer certificate, mechanic certificate with A&E rating, and radio operator certificate. He qualified on toeing 377s on March 28, 1956, and had accumulated 1,728 flying hours in B-377's. He received his last CAA physical examination m June 29., 1956.

Navigator Richard L. Brown, age 31, was employed by PAWA on December 9, 1955. He held a valid airman certificate with commercial rating., and a temporary CAA navigation certificate issued August 24, 1056. Mr. Brown had a total of 1,283:16 flying hours, of which 446:00 were in Boeing 377's. His last physical examination was passed on February 28, 1956. He had completed the initial emergency equipment training course - dry drill - on January 13, 1956


The cabin crew consisted of:

The Stewardesses Purser Pat Reynolds, Katherine Araki, Mary Ellen Daniel

Purser Patricia Reynolds, age 30, was employed by PAWA on September 23, 1946. She had completed her latest B-377 emergency equipment recheck on February 10, 1956, and had completed the USCG wet drill in San Francisco on July 12, 1956.

Stewardess Mary Ellen Daniel, age 24, was employed by PATTA on June 23, 1954. She had completed the B-377 emergency equipment recheck an March 12, 1956, the USCG wet drill on September 18, 1956.

Stewardess Katherine S. Araki, age 23, was employed by PAWA on March 26, 1955. She had completed the B-377 emergency equipment recheck on May 7, 1956.

The aircraft for this leg of the trip was a Boeing 377, registered as N 90943, S/N 15959. Pan Am owned the aircraft. The aircraft was named “The Clipper Sovereign Of The Skies”. She had accumulated 19, 820:51 flying hours. It was equipped with four Pratt and Whitney R4360-B6 engines, and four Hamilton Standard Model 24260 propellers. The aircraft and engines were in full compliance with prescriped methods and time limitations.
Complete overhaul and maintenance records of N 90943 were kept at San Francisco headquarters of the Pacific-Alaska Division. A study of these records disclosed that the aircraft had been maintained in an airworthy condition according to CAA-approved maintenance procedures. and was properly certificated and equipped. No discrepancies were noted in any of the records of N 90943.


Arriving at Pan Am flight dispatch Captain Ogg, First Officer Haaker and Navigator Brown were briefed on the current weather conditions at Honolulu and on the filed flight path. The weather they would experience on the filed flight route was not a factor for this accident.
The crew filed an IFR flight plan for an estimated flight time of 8 hours and 54 minutes. Captain Ogg had fleet service load fuel for a flight time of 12 hours and 18 minutes. The estimated gross weight at takeoff was 138, 903 pounds. The Max T.O weight for this particular aircraft was 144,000 pounds. The CG was located within the required range.
The agreed upon flight plan reads: Clipper Flight 6 is cleared to San Francisco via Green Airway 9 then track to Position 30* N 140* W at 13,000 ft., The climb to 21,000 Ft. on course to San Francisco. All three crew members agree with the Pan Am flight dispatcher and Captain Ogg signs the release form and flight plan
Out on the ramp at the aircraft Flight Engineer Garcia was performing his walk around inspection before entering the flight deck and getting ready for the prestart checklist after which the engineer gives the Ready To Start Engines Report.
At the same time Passenger services allowed the 24 passengers three of which were infants to board the aircraft 30 minutes prior to takeoff.
Running through their pre start checklist, to include around 32 different items that need to be pre set or checked.
The engine starting procedure for these massive and powerful R4360’s requires full attention of the flight crew. After all engines are started and checked the pre taxi check list is read.
As ground control gives flight 6 permission to taxi Captain Ogg adds power, with his right hand on the four throttles he advances them to allow the aircraft to roll away slowly. Grasping the nose wheel steering wheel on his left side near his knee he steers the aircraft t to the active runway.

20:24 HST... lining up on the centerline of the runway Captain Ogg advances the four throttles to about 2700 rpm and starts his takeoff roll. Around 100 to 105 IAS the aircraft will lift off. After rotating the aircraft the big B377 departs Honolulu and climbs safely away . As the aircraft climbs and a positive rate of climb is secured Captain Ogg, calls for “Gear Up” 1st officer Haaker moves the landing gear switch and confirms that the red lights go out as the gear locks up. As the gear retracts Captain Ogg applies the brakes to allow the wheel rotation to slow down and stop. to 13,000 feet with no problems experienced.
Cruising at 13,000 feet Clipper Flight 6 heads eastbound on a heading of 062 degrees true.

01:02 HST... Clipper 6 contacts Honolulu on HF and requests a VFR climb to flight level 21.0.

01:06 HST…Honolulu ATC approves VFR climb to 21.0

01:07 HST…Clipper 6 starts its climb to Fl 21.0

Note: The mid point of the flight would be around 1140 nautical miles from Honolulu. And was calculated to be reached at 01:31 HST,

01:19 HST…Clipper 6 levels off at FL 21.0.. The cruising speed was allowed to increase to 188 Knots.

01:19 HST…Stewardess Mary Ellen Daniel the on duty stewardess opens the flight deck door and asks the crew if they wanted coffee. Two of the crew did , but Captain Ogg wanted a Coca Cola.

01:20 HST…Suddenly stewardess Daniel hears the engine noise suddenly go to a loud stridency. The aircraft dips suddenly she staggers and has to grab hold to remain standing.

01:20 HST…First Officer Haaker who was flying the aircraft at this time requested Engineer Garcia to increase the power in order to increase the air speed. Haaker stated he noticed a vibration in the controls and an increase in the propeller noise.

01:21 HST… First Officer Haaker and Flight Engineer Garcia notice that the Tachometer for No. 1 engine is reading about 2,900 RPM. Haaker reaches overhead and activates the feather prop switch for No.1 engine. Reaching down on the engine control panel Haaker and lowered the flaps to 30 degrees.

01:21HST.. Engineer Garcia reaches overhead and immediately activates the No.1 fire switch gang bar, pulls back the No.1 throttle to the stop and cuts the mixture control lever for No.1 engine. Garcia also reduced the power on the other three engines in order to reduce the airspeed.

Note : During the procedure of feathering the prop and shutting down No.1 engine the engine actually exceeded the highest calibration on the engine No.1 tachometer.
From the onset of the engine prop going into over speed, Captain Ogg was out of his seat and working at the Navigators station with navigator Brown. He immediately regained his seat.

01:22 HST… After numerous attempts at feathering the No.1 engine were unsuccessful, Captain Ogg orders Engineer Garcia to cut off the oil supply to engine No.1 so that it will freeze the engine.

Flight Engineer B-377

01:24 HST… The flight crew notices a momentary decrease in the RPM , then a heavy thud, followed immediately by an increase in the prop RPM. The crew decided the engine had frozen and the propeller had uncoupled through a failure in the propeller drive mechanism, and was wind milling in the airstream.

01:25 HST… Captain Ogg calls Ocean Station November. And alerts the ship that they may possibly have to ditch the aircraft. The Coast Guard Cutter Pontchartrain determines with its radar that Clipper 6 is approximately 38 miles from the ship on a bearing of 256 degrees. The Pontchartrain also recommended a heading for ditching the to the crew
Captain Ogg also orders Engineer Garcia to increase power on engines 2, 3, and 4 to help check the rate of descent. At this time Engineer Garcia advised the Captain that No.4 engine was only developing partial power at full throttle. When Garcia advanced No. 4 engine to full throttle the readings were 2, 350 RPM: 80 BMEP, 23 inches manifold pressure; oil and fuel pressures were normal; fuel flow was 600 pounds per hour, oil temp, carb air temp and cylinder head temps were lower then normal; turbo supercharger operation appeared normal. There was a slight rise n manifold pressure and in cabin airflow when the No.4 turbo calibrating control was rotated to the full on position. When Garcia reduced RPM to 1,750, and closed the oil cooler and intercooler, and the cowl flaps to one half inch, The BMEP increased to 90 with 26inches of manifold pressure at the same fuel flow. Looking at his engine analyzer Garcia noted that all patterns were normal, oil temperature, and cylinder head temperature increased slightly, and the engine continued to operate.
Pontchartrain From The Aircraft

01:25 HST… Captain Ogg, Clipper 6 notified “November” that a ditching was imminent . In return the Coast Guard Cutter Pontchartrain plotting the aircraft on its radar gave the crew a heading to the cutter.

01:26 HST… The Pontchartrain immediately alerted other ships and aircraft in the area. They reported to Captain Ogg…The sea weather was clear, the sea exceptionally calm, the winds seven miles per hour from 60 degrees.

Note: During the descent the crew found they could maintain altitude at an airspeed of 135 knots with rated power on engines No. 2 and 3 and partial power on No. 4

01:26 HST… Navigator Brown gets a heading to home on Ocean Station November and has the Captain alter their course slightly. Captain Ogg , alerts the passengers to the emergency and instructs the cabin crew to prepare for a water landing.

01:37 HST… Just prior to over heading November, Flight 6 called its dispatch office in Honolulu and advised them of the situation.

01:37 HST… Clipper 6 arrives overhead Ocean Station November. Prior to arriving overhead November Navigator Brown and Engineer Garcia determined that the remaining fuel was insufficient for the aircraft to to return to Honolulu or to continue on to San Francisco. The range was seriously empaired by the drag created by the wind milling prop and the required lower airspeed. With the remaining fuel on board Navigator Brown computed the maiximum range of the aircraft as 750 miles. The distance to Honolulu or San F4rancisco was well over 1000 miles.
By this time Clipper 6 has descended to 5,000 feet. With an airspeed of 135 knots the crew could maintain this altitude with the flaps up and rated power on engines 2 and 3. Although the aircraft was allowed to settle to 3,000 feet just prior to over heading the cutter.

Note: It was found that the wind milling propeller could be kept under control if the airspeed was kept below 140 knots. . This airspeed is about 20 knots less than that required for efficient two engine flight.

Note: The actual procedure for a Propeller over speeding required the pilot flying to Maintain Directional

Pilot Flying:
Retard the remaining throttles to reduce forward speed.
Pull the aircraft up to hasten the reduction of forward speed.
If the situation warrants have the Flight engineer Feather prop.

Flight Engineer

Close Throttle
Decrease RPM
Prop Feather
Mixture Lever for the over speeding Prop Idle Cut Off.
Ignition Switch off
Complete engine shutdown checklist.

Over the Cutter

01:40 HST… Captain Ogg set up a shuttle pattern over November using the heading of 240 degrees while making eight mile legs. 240 degrees was the heading he will use for the ditching. At this time the cutter laid out a string of electric water lights along the 240 degree heading and was standing by for the aircraft to make its approach for the ditching.

02:00 HST… Captain Ogg after evaluating the situation with his crew decided that ditching by day is in itself a dangerous situation and doing it at night is even more dangerous. At this point knowing he never had ditched an aircraft, makes the decision to delay the ditching until daylight which is 3 hours away. In the meantime Captain Ogg orbited November.

02:15 HST…While talking with the captain of the Pontchartrain Captain Ogg voice held no tone of an emergency. At one point the Captain of the cutter mentioned that the aircraft carrier Bennington was coming to the scene, “Maybe you could land on the carrier” he joked. “I don’t think I‘ll try that”, the chuckling Captain Ogg replied.

O2:45 HST… The No.4 engine backfired and the power immediately dropped off. Engineer Garcia makes an analyzer check and this time the engine shows many low resistance shorts and no combustion pattern on the “B” row of cylinders. Captain Ogg, decides to feather the prop. Garcia reaches over head and feathers the No.4 prop successfully.

02:47 HST…Engineer Garcia set the remain two operating engines, No. 2 and 3 at 2,550 RPM, 190 BMEP and 2,000 pounds per hour fuel flow. The aircraft has settled to 2,000 feet and is flying at 140 knots.

03:00 HST…As the aircraft burns off some fuel weight, Captain Ogg allows the aircraft to climb back to 5,000 feet. At this time the crew perform a few practice approaches to feel the controllability of the aircraft out at the lower airspeeds. Captain Ogg, continues to circle over the cutter to burn as much fuel as possible in order to make the aircraft as buoyant as possible during touchdown on the water.


01:20 HST A sudden dip in the aircraft alerts the Purser Patricia Reynolds and stewardess Katherine Araki. It also awakens Mrs. Richard Gordon, who peered out of the berth she occupied with one of her daughters.


01:23 HST Pat Reynolds leaves the flight deck and returns to the cabin and tells the other cabin crewmembers that the number one engine was in trouble and the Captain was trying to “feather” it .
At this time other passengers sleeping in berths or blanket covered reclining seats began to awaken.

01:26 HST The PA announcement by Captain Ogg is heard by all the passengers. “Sorry to wake you up. “ He said regretfully, “but our no 1 engine is running wild and there might be the possibility of a ditching. Please put on your life jackets, strap on your safety belts and remove sharp objects from your pockets.”

Note : In the aircrafts cabin the passengers stated they did not feel any noticeable vibration or sense of losing altitude. There was just the high unnatural scream of the engine and the racing propeller.

01:27 HST Stewardess Pat Reynolds turned on all the cabin lights.

01:29 HST Checking her Pan Am crew manual for the procedure for ditching she read aloud to the passengers the rues for ditching: They were to bring their reclining seats to a bolt up right position. No smoking, takeoff their shoes and glasses, remove all sharp articles from pockets, pull their seat belts as tight as possible. The passengers did as they were told. According to the crew one woman ever tore the crucifix off her rosary. Stewardess Reynolds explained to the passengers when they gave the order to brace for ditching they were to bend over, resting their faces on in pillows laid in their laps and wrap their arms under their knees. She explained that they should stay in that position until they were sure the aircrafts motion had stopped, since the first shock might not be the last. Life jackets should not be inflated until they were out of the aircraft.

01:30 HST As stewardess Reynolds instructed the passengers all was quiet except for the roaring engine. She stated that no one cried out or betrayed alarm. Most of the passengers pulled out their life jackets and began putting them on without a word. A few asked for instructions.

01:33 HST It took just about three minutes to have all the passengers ready for the brace order.

01:37 HST… In the cabin the stewardesses pointed out the location of all the life rafts, and assigned several passengers to assist in the launching of the rafts. The passengers were then relocated to the safest seats, forward of the tail section, which captain Ogg had believed the tail may break off upon landing.

05:10 HST…In the cabin the stewardesses moved the passengers into seats near the wings; they repeated the ditching instructions once again. They made sure everyone had taken off their shoes and loose personal items were stowed away. The Captain reported regularly that there were plenty of ships coming t their rescue. Pat Reynolds walked down the aisle smiling and asking if anyone wanted a magazine. Mrs. Freida Dix of Jasonville, Ind. A grandmother of seven said, “Are you kidding” and everyone laughed a little. The stewardesses served coffee and orange juice, Katherine Aralki passed chick lets around.

05:15 HST… Captain Ogg announces “We will not be ditching the aircraft for at least an hour. If any passengers wish they could get up and stretch their legs and relax with a smoke if they wanted to”, he said.


Note: In the process of ditching the pilot will fly the aircraft with power on till the last second before flaring in order to settle into the smoothest spot he can see. The danger of ditching lies in the last few seconds of rapid deceleration as the plane touches down o n the water. The flight manual would state the Stratocruiser should attempt ditching with the nose being held about 5 degrees above the horizon.

When daylight broke over the ocean , the sun rose warm and brilliant over a level and blue green sea whose waves were only three or four feet high.

05:00 HST…A revised heading is given to the aircraft for the ditching. The heding will be to the north west at 315 degrees.

Laying Foam On Ocean

05:30 HST…On the Pontchartrain the crew removed the water lights and requested they be notified 10 minutes prior to the time the flight intended to touchdown. This would enable them to be in absolute readiness and allow sufficient time for them to lay a foam path to mark the revised ditching path of 315 degrees.

05:40 HST… As daylight arrives Captain Ogg contacts the cutter and notifies them of their intended ditching time.

05:50 HST…Captain announces to the cabin to take their seats and prepare for the ditching.

05:52HST… Captain Ogg, descends thee aircraft to 900 feet and makes a practice approach on the heading of 315 degrees.

05:55 HST…Captain Ogg, announces over the cabin PA system “Ladies and Gentlemen the water temperature is 74 degrees and the waves are only a matter of inches high. There is absolutely nothing to worry about-things couldn’t be better for us. I’ll soon give you a ten minute warning. Then one minute before touchdown I’ll tell you this is it, Do as the stewardesses tell you please.

06:05 HST… Engineer Garcia jetted carbon dioxide into the wings, a precaution in case of fire. The Pontchartrain spreads a path of fire extinguisher foam on the water, a runway like path some 2,500 yards long and 100 feet wide, this also gave Captain Ogg a point of reference and helped reduce the danger of fire after ditching.
Captain Ogg, announces “10 minutes to ditching time.”

06:13 HST…Captain Ogg, turns and makes his approach , he lines the aircraft up on the spread foam laying on the ocean surface that is perfectly visible from the cockpit. He orders full flaps and slows the aircraft to 90 knots with the gear retracted.

06:13 HST… Second Officer Dick Brown the Navigator, leaves his seat in the cockpit and enters the cabin rushing past the bent over passengers and takes his place near the main door, which he is assigned to open.
Captain Ogg announces over the PA system….”One minute” ..”This is it”.

06:15 HST…With Captain Ogg flying the aircraft, First officer Haaker and Engineer Garcia brace themselves as best they could, which was very little in the cockpit and watched the final seconds till touchdown.
First contact with the water was slight, followed almost immediately by a tremendous impact. The aircraft was partially driven under water but bobbed quickly to the surface and stopped with very little forward travel. As anticipated. the fuselage broke off aft of the main cabin door. Several unoccupied seats remained in this section. A number of seats forward of the fracture were torn loose and several passengers were hurled to the floor. Two children who were being held were thrown from their mothers arms. There were no fatalities or major injuries and no occupants were incapacitated by the crash; however. five people received minor injuries.
Stewardess Katherine Araki told herself, “ Its going to be all right.” Then there was a sudden great shook , followed by a second and worse shook. Passenger Mrs. Jacobe’s daughter Joan was twisted from her arms and so was Maureen Gordon from her mothers arms. There was a sound of thin metal being crushed and crumbling and a sound of water rushing in.

Much of the planes freight was in the lower compartments, in that instant two dogs and 3,300 canaries and a parakeet presumably died! Merchandise of varying types was all lost.

Clipper 6 Hits The Water

Spins off the left in mist

Comes to A Halt

06:18 HST… After the aircraft stopped, members of the crew and the passengers assigned to assist removed the Emergency exit doors. First Officer Haaker went to his emergency station at the port wing, where Stewardess Araki was already telling some men passengers how to take down the life rafts above the windows.

Engineer Frank Garcia took charge of the life raft on the starboard side. Second Officer Dick Brown had the main door open and stewardess Mary Ellen Daniel found herself behind him. It was where she was supposed to be but she did not recall going there.

Brown pushed the life raft out the door and inflated it. It partially blocked the doorway and Stewardess Pat Reynolds and Brown shoved until it dropped into the water. The passengers began dropping into the raft and when stewardess Daniel jumped in she looked up and saw the Pontchartrain speeding toward them like a colt. But the raft was hemmed in next to the fuselage by the left wing and the broken off tail that had drifted alongside.

First Officer Haaker, directing port side operations from the wing ordered the passengers in the raft to climb onto the wing and then get into the other raft, which had been launched between the two engine nacelles on the port side. The women went first while the men held the raft steady while they walked across the wing without slipping. There was no shouting, only low voiced instructions.

The Hero Captain Richard N. Ogg Last To Leave The Aircraft.
Captain Ogg, and Purser Reynolds were the last t leave the aircraft.

A Coast Guard boat came up alongside the raft almost immediately/ The Coast Guard men said very little. They looked like men in a hurry and they threw the raft a line. And pulled the raft away from the sinking aircraft which by now was nose down in the water with the end of the broken and shattered fuselage with a dangling and unused life raft hanging in the air. The rescue was clean and quick.

The Coast Guardsmen helped passengers out of the rafts and into the boats and brought them to the Pontchartrain ladder. As they climbed onto the deck of the Cutter sailors stood in line each one holding a blanket and wrapped the passengers and asking” Can I get you a cup of Coffee?”.

NOTE : Two 20-man life rafts were launched through the emergency exists over the wing and one raft was launched through the main cabin door. All occupants then evacuated the aircraft successfully through these exits. The life raft that had been launched from the main cabin door was trapped against the wing and fuselage by the broken tail section, which had swung to the left. Sane of the occupants transferred over the wing to another raft, enabling the first raft to be freed. The raft launched between Nos. 1 and 2 engines did not inflate properly and filled with water while it was being pulled clear by a Coast Guard rescue launch. All of the occupants of this raft were, immediately transferred to the rescue boat without further mishap. The remaining passengers and crew, who evacuated the aircraft on the starboard side were then transferred from the raft to the cutter Pontchartrain.

06:35 HST…. The “Sovereign Of The Skies” sank .


Since there was no opportunity to examine the aircraft engines and propellers. this analysis must be based on the most logical conclusions drawn by experience and knowledge from the evidence available.

The Board is of the opinion that two separate and unrelated mechanical malfunctions occurred during this flight and the relationship of each failure to the accident should be treated separately.

N 90943 was powered by four Pratt and Whitney R4360-B6 engines and equipped with Hamilton Standard. model 24260, propellers. The initial difficulty encountered resulted in the overspeed of No. 1 engine and inability to feather its propeller. Engine r. p. m. is normally maintained by engine oil
at boosted pressure which is directed by the propeller governor to either side of a piston in the propeller dome. Movement of this piston changes propeller blade angle to maintain the desired r. p. in. Feathering is normally accomplished by auxiliary pump oil taken from the engine oil supply tank and directed by the governor through passages used for r. p. m. control to the outboard side of the piston. Consequently. a portion of the governor and the increased pitch side of the dome piston are common to both feathering and constant speed operation. It is considered most likely that the inability to feather was caused by the sane malfunction which resulted in the original overspeed. If the auxiliary pump had failed there would have to have been a second near-simultaneous failure in the propeller system. This possibility is considered to be remote. Further more. depletion of the oil supply from the No. 1 tank. subsequent to the overspeed, with no external signs of leakage. is most logically attributed to operation of the auxiliary pump during attempts to feather following the stoppage of the engine by freezing.

The most likely causes of the overspeed and inability to feather are that oil was being misdirected at the governor pilot valve or that there was insufficient oil pressure at the do-me piston. Improper direction of the oil would involve governor malfunctions, caused either by a fault within the unit itself or by contaminated oil being supplied to the governor. Contaminated oil would indicate some failure with the engine which would most likely be of a progressive nature. No such failure was evident to the crew prior to the overspeed. Insufficient oil pressure at the dame piston is most generally due to excessive leakage. Leakage usually involves seals, passages. transfer tubes., or bearings in the propeller, propeller control, or the engine.

The Board believes that a sing] e failure occurred which affected the portion of the system common to the constant speed and feathering portion of the propeller control system. Oil was being delivered to the system by 'the feathering pump and then dumped into the engine. A more specific reason for the overspeed cannot be determined.

Subsequent to this accident PAWA Pacific-Alaska Division experienced two uncontrollable engine overspeeds and inability to feather propellers due to failure of the propeller oil transfer bearing. A redesigned propeller oil transfer bearing has been provided by the manufacturer and its use was made mandatory by CAA Airworthiness Directive issued March 25, 1957.

From the information available concerning the No. 4 engine, it would appear that the initial power loss resulted from a reduction of the air flow through the carburetor. Fuel to the engine is metered by the carburetor in pro-portion to the air-mass flow through the throttle body. Engine instrument readings reported by the crew indicate oil and fuel pressures were normal but that temperature indications and fuel flaw were low. Turbo supercharger responses indicated that that system was at least partially operating. These conditions could result from an obstruction caused by a deformation or partial breakup and displacemnent of the carburetor inlet air duct system. or a failure of the engine-driven impeller drive assembly. Although the first possibility cannot be completely discounted, the latter appears to be more probable.

It is significant to the analysis that PAWA records indicate three engine-driven impeller drive failures on like engines prior to this accident. The BMEP and manifold pressure readings. taken subsequent to one of these failures, were almost identical to those on No. 4 engine in this accident. Also, in the prior engine failure the crew reported light back-firing approximately one minute after the propeller drive failure and the propeller was feathered immediately. In the subject accident the engine continued to ran at reduced power for some time before backfiring commenced. Men, indications of many low-resistance shorts and the lack of combustion pattern on the B row of cylinders were observed on the engine analyzer. This evidence is not inconsistent with an impeller drive failure. With the failure of the impeller drive assembly, impeller rotation would stop thus reducing the airflow which in turn would reduce the fuel flow. Turbo supercharger air and normal engine breathing would provide a limited combustible air-fuel mixture to the cylinders; however, distribution of the mixture to the cylinders would be impaired. It is believed, therefore, that all of the indications reported by the crew of Flight 6 could result from the engine-driven impeller drive assembly failure.

Following these failures, the basic design of the Pratt and Whitney R-4360-B6 impeller drive was re-evaluated by the manufacturer and the CAA. No design deficiency was found to exist and it was concluded that this type of failure is not chronic with this model engine. As a result of this study the Board concluded that the design of the impeller drive is adequate and that no corrective measures are necessary.

With the propeller windmilling the range of the aircraft was unquestionably reduced to less than that required either to return to Honolulu or continue to San Francisco. Required fuel for the subject flight was computed an the basis of two-engine operation; therefore, only if the crew had been able to feather the No. 1 propeller and maintain the most efficient two-engine airspeed (165 knots) could it have reached land.

Data received from Hamilton Standard and Boeing, and derived from calculation and tests of the subject type propeller, indicate that the drag resulting from this propeller with the blades on the low pitch stops, 21.3 degrees, 145 knots. 2,000 feet m. s. l., would be:

Uncoupled windmilling
520 lbs.
Coupled windmilling

The additional power necessary to compensate for the additional drag in each of the above conditions is:

BHP (Brake Horsepower)

Since drag resulting from these conditions varies as the square of the velocity, it is evident that exceedingly higher drag forces would be encountered at speeds greater than 145 knots.

This drag information is extremely important because prior to the investigation of this accident it was not widely known. In fact. it is believed. many thought that the drag with the propeller windmilling and coupled was greater than that with the engine and propeller frozen., whereas the drag condition is greatest with the engine and propeller rotation stopped. It is noted, however that the above data apply only to the subject aircraft and propellers.

The Board believes that this report would be incomplete without a word of praise concerning the handling of this emergency by all the personnel involved. The Board highly commends the crew members for their ability in recognizing the malfunctions and taking correct emergency actions consistent with all known procedures. Their calm and efficient control of the situation averted what could have been a major air disaster.

In addition, the prompt response by the Coast Guard to the emergency and the immeasurable assistance rendered to the flight are deserving of particular Praise.


On the basis of all available evidence the Board finds that:

The company, the aircraft, and the crew were properly certificated and the flight was properly dispatched.

The aircraft was properly loaded with respect to gross weight and center of gravity limits.

The flight was normal until the control of the No. 1 propeller was lost and the engine oversped.

It was impossible to control the engine speed or to feather the propeller.

The engine was frozen, however. the propeller became decoupled from the engine and continued to windmill.

There was a partial power loss on engine No. 4; it subsequently failed completely and the propeller was feathered.

Airspeed was restricted to 145 knots to prevent the windmilling Propeller from overspeeding.

Range of the aircraft was so reduced that it was impossible to reach land.

The passengers were thoroughly instructed in correct emergency procedures and the aircraft was ditched under control with no fatalities.

Evacuation of the aircraft was well planned and orderly.

Probable Cause

The Board determines that the probable cause of this accident was an initial mechanical failure which precluded feathering the No. 1 propeller and a subsequent mechanical failure which resulted in a complete loss of power from the No. 4 engine. the effects of which necessitated a ditching.