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Aviation History
1990
1990 - 1356.PDF
LETTERS 737 rudder trim changes needed SIR—The recent reports carried in Flight of rudder trim problems on the Boeing 737-300/400 are not isolated cases. The Air Line Pilots Association (ALPA) has identified a relatively large number of occasions when pilots have found the rudder trim in the wrong position. To the end of February, 88 cases had been reported to the Federal Aviation Administration (FAA). These fell into the following categories: electrical anomalies, 5; indicator malfunctions, 21; sticking rudder trim knob, 27; inadver tent operation by jumpseat rider, mechanic, other, 35. The FAA has recognised the problem with the system and issued three proposed airworthi ness directives for the redesign of the system. ALPA believes that other changes are required, such as an aural rudder trim-in-motion warning and incorporation of rudder position in the take-off warning system. HAROLD MARTHINSEN DIRECTOR Accident Investigation Department Air Line Pilots Association 535 Herndon Parkway PO Box 1169 Herndon, VA 22070 USA Revising a two- crew equation SIR—Comment (1 April, 1989) was headlined with the equation 2+2=?. Wils dt Vries, writing about the KLM all-engine flame- out over Alaska (Letters, 7-13 March) adds another element to this equation. It is not clear whether it is general airline practice on long- range two-pilot operations to permit each pilot to have periods of up to 15min away from the flightdeck, as reported. This would mean, if each pilot took his turn, periods of up to 30min in which a single pilot is "mind ing the shop". It is not stated if this can occur only once during the flight. An aural trim-in-motion warning is needed for the 737, ALPA believes This suggests that a significant proportion of cruise flight is single-, rather than two-pilot, operation. It is open to doubt whether this was anticipated during original certification of the aircraft and whether it meets the intention of FAR 91.7. Perhaps the headline could be more appropriately written as 2+1 = ?. The answer to that equation might be more than A $. E BORREMANS 8 Kouterweg 1981 Vossem Belgium Need to resolve TOPM problems SIR—Take-off performance mon itors (TOPMs) again? Now be serious, chaps. Lines painted on runways. Not easy to spot, I would have thought, at 170fps, with a runway visual range of 125m, while monitoring all other aspects of the take-off. Time to 80kt might be better. The indica tors are inside the cockpit and that speed is not too fast for a safe rejected take-off. Computerised systems are probably inevitable, but the fol lowing problems need to be re solved; system reliability; sim plicity and unambiguity of presentation; increased number of rejected take-offs; the possibil ity of TOPM-induced overruns; the non-field-length-limited take-off (V, GO and V, STOP); air temperature measurement at runway surface and air-intake level; varying slopes along the runway surface; variation in runway surface friction; varia tion in line-up distances; rolling and static take-offs; rate of take off power application; normal- rated or flexible-thrust take-offs; windshear. NORMAN FOSTER 11 St Peter's Street Duxford Cambridge CB2 4RP TOPM funding SIR—The article "CAA funds take-off system" (Flight , 7-13 March) misrepresents the UK Civil Aviation Authority's posi tion regarding the funding of Bristol University's take-off per formance monitor (TOPM). The CAA visited Bristol Uni versity on 1 February to discuss the status of the TOPM work with a view to the possibility of supporting further work from the CAA's R&D. It was explained to Bristol University that the possibility of any CAA R&D funding would be contingent on it identifying a cost- and risk-sharing industrial partner and some positive input from the airlines. A costed pro ject proposal would then be re quired to be submitted to the CAA before any R&D funding would be considered. To date, no such proposal has been received. C G HOWELL CHIEF SCIENTIST Civil Aviation Authority CAA House 45-59 Kingsway London WC2B 6TF WHAT'S ON 5-7 June SAL seminar "Hypersonic Propulsion", by Frederick Billig. Mun- chen Park Hilton, Am Tucherpark 7, 8000 Munchen 22, West Germany. Also at: (20-22 June) Hotel Ambassador, Paris; (25-27 June) Mount Royal Hotel, Marble Arch, London Wl. Contact: SAL HP Seminar, Victoria House, Suite M9, Southampton Row, London WC1B 4EF; tel: 071-404 3341; fax: 071-405 6203. 11-14 June ASME international gas turbine and aero-engine congress and exposition. International Conference and Exhibition Centre, Brussels, Bel gium. Tel: Marcus Stone (Inco Alloys International), Bristol, (0272) 292311. 11-15 June Astelab 90, international symposium and exhibition, "Industrial Tests, European Co-operation". Pare des Expositions, Porte de Versailles, Paris. Contact: Association pour le De- veloppement des Sciences et Tech niques de l'Environnement, ASTE, 8 Rue Roquepine, 75008 Paris, France; tel: (1) 42 66 58 29; fax: (1) 42 66 12 06. 12 June 1SSC seminar, "International Simulation and Training Market—re quirements, specifications, applica tion". Holiday Inn, Brussels Airport, Belgium. Contact: Erika Maier, Heils- bachstrasse 26, D-5300 Bonn 1, West Germany; tel: 4-49 (0) 2 28 64 83-168; fax: 4-49 (0)2 28 64 83-174. 12-15 June IATA conference and exhi bition, "Information Technology: how successful is information technology's contribution to airline productivity and cost control?". Hotel Plaza Concorde, Mice, France. Contact: David Durward, International Air Transport Associa tion, PO Box 672,' 1215 Geneva 15 Airport, Switzerland; tel: 022-799 2713; fax: 022-799 2683. 14-17 June Cayman Islands Annual Aviation Safety Seminar. .-Grand Cayman. Contact: Charlotte "fLatham, Cohen Associates, 250 Catalonia Avenue, Suite 801, Coral Gables, FL 33134, USA; tel: (305) 443-1151. The opinions expressed in these pages do not necessarily represent those of the Editor. Flight Inter national cannot undertake to publish letters without name or address, and reserves the right to select or edit letters. 711 FLIGHT INTERNATIONAL 9-15 May 1990
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