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Aviation History
1971
1971 - 1028.PDF
FLIGHT International, 24 June 1971 915 747 STATUS REPORT WITH about 140 units delivered and 300,000 flight hours under its belt the Boeing 747 has turned in an average daily utilisation of 8-14hr on sectors averaging 4-7hr duration since the first delivery was made at the end of 1969. This is despite early troubles and exposure to two winter periods. At the end of April, the average mechani cal scheduled reliability of the current fleet was 95-5 per cent. During its first year of operation the aircraft accumu lated flying time nearly twice as quickly as its predecessors and one airline achieved a utilisation of more than 15hr per aircraft per day during its initial operating period. For the week ending April 22, reliability varied from 88 per cent to 100 per cent according to airline. One of the airlines with no delay-causing malfunctions averaged 13hr a day. The million-hours mark has been passed by the JT9D powerplants. As at April 1 the then current mean time between premature engine removals was l,130hr, with mean time between in-flight shut downs being 2,640hr. This month the first higher-thrust powerplant—the JT9D-7—became available from Pratt & Whitney. Climb thrust is 1151b higher at 10,8151b (ISA+10°C) and a wet take-off thrust of 47,0001b can be maintained to 30°C. This compares with a 45,0001b rating to 26-7°C for current JT9D-3As. Dry thrust goes up by 2,0001b to 45,5001b at the latter temperature. First delivery to both SAA and Qantas (in the latter's third 747) is expected in October. Certifica tion of the aircraft, when fitted with new quieter intakes with no blow-in doors, should be completed in November with deliveries anticipated in December. An extended downstream fan flow splitter ring is fitted together with extensive areas of acoustic lining. The initial climb performance of 747s has come in for criticism of late, but BOAC management at least is confident that its 747s, which have fully modified JT9D-3As, with no restrictions on using rated thrust, can fully meet London ATC requirements with respect to climb gradients. At a typical weight for a flight out of London for New York the aircraft can, it is claimed, readily reach 4,000ft at Woodley some 17 n.m. from the start of take-off "at all reasonable temperatures." At maximum weights this requirement can still be met and the aircraft takes 245 n.m. and 38min to reach its cruising altitude—only 40 n.m. and 4min longer than the 707 on a non-stop flight to the US West Coast. Four minutes is again the differential on the New York run. Boeing continues its 747 structural testing. No significant failures have occurred during 20,000hr of fatigue testing subsequent to the inspections at the 18,000hr mark. These revealed failures in flap tracks, in the sides of body ribs, and in the keel beam centre web. Modifications have been incorporated in all aircraft delivered since April. Other components have exceeded design objectives. Current negotiation with the FAA over the adequacy of escape doors will, if successful, allow up to 575 passengers to be carried. The present maximum is 500. The upper deck is already on offer with increased capacity. The 537-seat SR version, which is on offer for high-density short-haul routes, has had its take-off and landing weights selected to allow unrestricted use on the shorter routes, while paper studies still exist for physically stretched versions of the aircraft. The first 747 freighter is now undergoing major assembly ready for roll-out in early October, a first flight in December and delivery to Lufthansa in May 1972. A growth version with a gross weight of 800,0001b is proposed. Already a 747B has been flown at 820,7001b, setting an unofficial record maximum take-off weight in the process. 747 SR PROJECT DETAILS Domestic Domestic all economy all economy (32in pitch) (33in/34in pitch) Regional International mixed class mixed class Certificated take-off weight (Ib) 520,000 Certificated landing weight (Ib) 505,000 Certificated zero-fuel weight (Ib) 475,000 Operating empty weight (Ib) 345,000 Passenger capacity 537 Powerplant JT9D-7 (Derated) Thrust (sea- level static, Ib) 43,500 (dry) 520,000 505,000 475,000 344,500 501 JT9D-7 (Derated) 43,500 (dry) 600,000 710,000 (735,000 available) 505,000 564,000 475,000 353,400 448 JT9D-7 (Derated) 43,500 (dry) 526,500 361,500 371 JT9D-7 45,500 (dry) Stretched Arava likely Israel Aircraft Industries announced at Paris that the Arava will be developed beyond its present 12,5001b, 5,670kg weight limit and that a 30-seat version is planned. The fuselage will be extended before and behind the wing and power will be increased by adopting the PT6-40 in place of the -27; the power unit change is likely to be accompanied by a change to four- bladed propellers as used on the Short Skyliner. 747 MECHANICAL SCHEDULE RELIABILITY Airline B H K M N O Av'Q Schedule reliability 93-7 980 98-2 90-3 94-5 97-4 96-3 94-9 97-3 88-1 97-7 95-8 96-2 1000 1000 1000 96-8 95-5 (per cent) Average daily utilisation (hr) 8-10 7-69 707 8-71 11-48 8-71 11-57 6-81 7-90 8-38 9-43 8-14 11-10 5-93 9-36 13 00 900 7-51 week ending April 22,1971 / Seen at Montreal (Dorval) Airport on its delivery flight from Manchester, this HS.748 is now operated by Air Gaspe on passenger services between Quebec City, the lower north shore of the St Lawrence (including the Magdellaine Islands), Anticoste and the Gaspe peninsular. With the recent order for two Hawker Siddeley 748s from the Royal Australian Navy sales of the type reached 250. The 198 aircraft for export are worth over £100 million. The million- flight-hours mark was passed in February and more than 20 million passengers have been carried by 49 operators in 32 countries
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