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Aviation History
1960
1960 - 0187.PDF
FLIGHT, 5 February 1960 187 BOAC's Boeing 707s are all to be modified prior to delivery from Seattle. Basil Smallpeice, managing director of BOAC, commented that "We trust it will not cause a serious delay" AIR COMMERCE BOAC, Boeing and the Board WHILE Boeing still claim on-the-nail or early delivery for every707 so far, by the time BOAC's first -420 reaches London this claim will no longer be valid. It came as something of a shock,although not as a complete surprise, that following flight tests by E. P. Davies, the Air Registration Board's chief test pilot, Britishapproval of the 707 was still withheld. The issues are quite separate from those affecting take-off performance (Flight,December 25). Unease at the aircraft's behaviour is apparently concerned withthe three training incidents which occurred last year, two of which resulted in fatal accidents. In each case, it was lateralbehaviour of the aircraft at slow speeds that was called to question, although it is believed that the initiating actions were quitedifferent in each case. The two incidents in which engines were shed—over France in February and Seattle in September—wereapparently the result of demonstrations, possibly inadvertent, of conditions outside the normal flight envelope. On the other handthe American Airlines' accident over Long Island in August during a two-engine approach in a gusty crosswind could not be explainedin this way, although again it was suggested that had a different technique been adopted the accident might have been averted. From the violent rolling manoeuvre that developed on eachoccasion it may be inferred that roll and yaw control demands higher-than-average pilot skill under asymmetric thrust, at lowspeeds, and in adverse conditions—a conclusion that is borne out by Boeing's intention to increase the -420's fin height by a drastic35in, to add a small ventral fin and to provide full rudder boost on the Boeing 707-120. (The -320 and -420 rudder is already power-boosted beyond 15° travel to counter additional engine thrust, and the Qantas -138s were modified similarly before delivery.) Another707 modification apparently found desirable is duplication of the yaw damper, and this again points to Boeing's persuasion thatlow-speed flight is a regime where control could be improved. It should be made clear that although the -420s are to be modified atARB's behest, Boeing have conducted on their own account a similar programme with other aircraft in the 707 series. The firstmodified 707-420 will be ready for trials in the early part of this month and it will again be flown by Mr Davies before it is finally accepted and handed over to BOAC. But while it now seems probable that all future 707s may bemodified as part of normal design improvement, it is not clear if retrospective action is contemplated, nor who would pay for it if itwas. All deliveries made so far have been under FAA certification or validation, and unless this certification standard is changed (andthere is ample precedent for this in the past history of 707 approval) it would at first sight seem to be incumbent upon airline customersto request and pay for modification action themselves. What is involved is a matter of opinion about pilot skill, andperhaps this makes the modifications under discussion different from mere design improvements. As a matter of policy Boeingmay thus take responsibility for the modification upon themselves. After the accident at Long Is'and last year it was questionedwhether, with the lessened likelihood of a pilot experiencing full asymmetric turbojet failures, a training demonstration of this kindshould now be needed. And the FAA demanded that this type of exercise, tacitly admitted to be a difficult condition with a swept-wing aeroplane, should be attempted only at altitude. The ARB's insistence on modification suggests a philosophy thatif a redeemable failure case exists, it must be demonstrated, and pilots must be trained to handle it. Indeed, looking back on theFAA's "high altitude only" rule, it is easy to argue now that this could only have been thought of as an interim measure and thatthe FAA too must be concerned that low-speed asymmetric control must be improved until it is no longer a hazard. Looking at the particular modifications a little more closely, thefin extension (and rudder boost in the case of the -120) are obvious ways of improving asymmetric-thrust control at low speeds. This isadversely affected by sideslip or yaw of the swept wings, because rudder tab effectiveness is reduced. Another gain will accrue fromthe ventral fin. It has incidentally been suggested that this fin could act as a tail bumper and so reduce any penalties that mayresult from an excessively nose-high ground angle. The full take- off story has yet to be told, but it now seems to have been success-fully demonstrated that the geometry of the 707-420 is such that ground stall does not occur and that only revision of the flightmanual requires to be completed. BOAC's TOP PEOPLE FOLLOWING the Daily Mails forecast of "A Big BOAC* Re-Shuffle" (see Flight, January 22) came a report in the Daily Telegraph repeating that the chairman, Sir Gerard d'Erlanger,and the deputy chairman, Sir George Cribbett, would resign. The newspaper added that Eric Rylands of Skyways was to begiven Sir George Cribbett's primary responsibility of chairman- ship of BOAC Associated Companies Ltd. At first none of these reports could be confirmed in the appro-priate quarters. Then on January 31 the Minister of Aviation, Duncan Sandys (who was in South America with Sir Gerard),issued the following statement: — "In view of speculation that has arisen about the membership of theboard of BOAC I should like to make the position clear. Last November Sir Gerard d'Erlanger told me that on account of demands of his privatebusiness he would not wish to continue as chairman of BOAC after expiry of his current term of appointment in 1961. "A day or two before my departure for South America the deputychairman, Sir George Cribbett, informed me that for reasons of health he would not be able to continue for more than another three months.I therefore must reluctantly accept this resignation with effect from April 30. "I have not as yet taken any decisions about future appointments." THE ELUSIVE ALL-FREIGHTER * TTHREE sets of specifications for the Lockheed GL-207 Superx Hercules and the swing-tail Canadair CL-44D have failed to rneet the requirements of American Airlines, according to WilliamLittlewood, vice-president equipment research, in route-case evidence before the CAB. American, he said, were studying pro-posals for both turboprop and jet all-cargo aircraft in an attempt to meet their requirement for aircraft in the 40,000-60,0001b and80,000-iqO,0001b payload capacity class for intermediate and long haul service. He specified a d.o.c. of between 4c and 5c per c.t-m.Both Lockheed and Canadair were, he said, refining and improving their specifications. Earlier he had told the CAB that animproved version of the Super Hercules, the GL-207-23, with a gross weight of 200,0001b and a maximum payload of 77,4001bwas "penalized by the length requirement for landing." This was said to be 8,350ft. The aft-fan versions of both the Boeing 707 andthe DC-8 were being examined by American: he gave the pay- load of the 315,0001b Boeing 735 as 93,766lb. There are twoversions of the Model 735—the -28, priced at about $6,825,000, and the 735-30 with higher weight and increased thrust pricedat about $8,025,000. In addition to American Airlines, Slick Airways is also reported to be interested in the Boeing 735. Pictured outside the Sud factory and control tower at Toulouse is the first Carayelle for Air Algerie, delivery of which was accepted early last month. It has been in service for nearly five weeks
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