FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1967
1967 - 0120.PDF
118 FLIGHT International, 26 January 1967 AIR TRANSPORT . . . The Changing Fire Hazards THE LESSONS TO BE LEARNED from a survivable accidentinvolving fire (actually that to the United Air LinesBoeing 727 at Salt Lake City on November 11, 1965, on which the CAB report was issued in June last year) are dis- cussed in the latest issue of the Flight Safety Committee's Focus. In this accident a heavy landing short of the runway resulted in undercarriage failures which, in turn, caused fuel line and other failures followed by fire. Of the 90 occupants, only 50 escaped from the burning and smoke-filled fuselage and of these two died later from fire injuries. Focus deals first with the sequence of events following the accident, in so far as these concerned the fire and the evacuation, and then discusses the lessons to be learned. "In previous aircraft crash-fire accidents," Focus says, "the mainfire has been initially exterior to the occupied fuselage sections, with flames entering the cabin areas because of failure of the skin fromheat exposure, or rupture of wing centre-section tankage, or through the wing roots (where the wing adjoins the fuselage). Inthese "normal" crash-fire behaviour patterns, the severity of the fires has been influenced primarily by fuel-tank failures and massivefuel spillage. "In this accident, failure of the gear and the impact did notdestroy the tightness of the integral fuel tanks in the wings. The landing gear pulled free before tank rupture, fulfilling an aircraftdesign criterion. After fire extinguishment all the fuel tanks were found intact and 3,450 gallons of kerosene were pumped out ofthe tanks during salvage operations. The fuel problem in this case came solely from the rupture of the interior lines running from thewing tankage area to the rear-mounted engines and only a few gallons actually burned—almost certainly less than 100 gallons. "Although aircraft structures have been improved for more andmore resistance to crash-impact forces and good progress has been made in de-lethalising cabin seats and equipment from the viewpointof occupant injury, fire, regardless of its source and how it is fed, is becoming more crucial as far as accident survivability is concerned. "Detailed testimony from survivors shows that many passed byusable exits. This can be attributed in part to the dense, choking smoke that prevented the crew and others from giving instructions,since speech was impossible and visibility was near zero within seconds following the initial outbreak of fire. If the emergencylights did operate they could not be seen. Many of the passengers were so disoriented as to their location they did not know whichway to turn. From data on the location of the bodies recovered, it is evident that many in the rear seats ran forward even before theaircraft stopped skidding. The greatest concentration of bodies was just forward of the centre galley area in the aisles around seat six.The reason for the forward movement of the passengers is that the earliest sign of fire was in the aft section of the cabin. Also, otherexperience indicates that people naturally tend to try to escape exactly the same way they entered the aircraft—in this case, by theforward entrance. "The cabin interior materials used in modem-day jet aircraftmust meet prescribed Federal Aviation Agency tests for flame resistance, but several recent aircraft cabin fires point an accusingfinger at cabin interior finishes. This subject was discussed at the 1966 NFPA Aviation Fire Safety Seminar held during the NFPAannual meeting. Perhaps it would not be reasonable to expect any materials to withstand the type of flame attack prevailing in thisaccident. In this fire, however, the materials clearly contributed to the extent of the fire, if not to the loss of life. "Effort should certainly be made to develop equipment that couldproduce effective fire control within the cabin to extend survival time. Despite several attempts in this direction, no hardware hasyet been developed for the purpose. A sprinkler system employing the aircraft's limited water supply is one possibility—but to datethis solution has not met acceptance because of the limitations on the water supply and the weight problem of carrying additionalwater solely for sprinklers. The most recent proposed answer is to utilise high-expansion foam, but its successful employment is ques-tionable. While there is little doubt that passengers could survive in such an atmosphere, their orientation might be seriously affectedand there are psychological problems involved—whether foam would act as a panic suppressant or a panic generator is a questiononly comprehensive tests could establish. In any case, it is clear that present ground fire-fighting forces do not have the capabilityof quickly controlling aircraft interior fires, and further investiga- tion of this subject is indicated. "Airframe manufacturers and the Federal Aviation Agencyhave undertaken study of the location of the fuel lines in aircraft with rear-mounted engines, and the proximity of such lines to theexterior aircraft skin and to electric power cables, in an effort to determine whether re-location or re-design would reduce the possi-bility of such damage as was caused in this accident. The fuel lines in this aircraft were aluminium-shrouded, with the shroudssealed, vented, and drained outboard. These shrouds extended from the fuel tank exit point in the rear spar through the cabinfloor beams in the cargo compartment to the struts and the centre- engine fire wall. The fuel lines and shrouds passing through thepressurised areas were continuous, with no joints or connections. "All these design factors are aimed at fire prevention, but, inthis case, where the landing gear shattered the fuel lines to the engine, the safeguards proved ineffective. The lines were roughly8in to lOin from the outside skin of the aircraft fuselage and the question is whether re-locating them to avoid the kind of damageencountered in this accident would be desirable. The FAA is con- sidering stainless steel lines and shrouds or stainless steel sheathingwith a Reflon(R)-type covering and a neoprene core. "While not a factor in this accident, the fire department responsetime was not favourable. Efforts must be made to speed up fire department response to the scene of every airport fire emergency.Particular attention must be given to the problems of accelerating and increasing the cross-country mobility of airport rescue andfire-fighting vehicles, strategically locating airport fire stations for immediate access to the approach and departure ends of the runwayand even improving fire-station interior layout to minimise the time fire and rescue crews take to get equipment on the roll. An instan-taneous alarm has little value if there are unnecessary delays in 'reaction time.' "For years aircraft fire crews have been taught to keep the fuse-lage cool and to drive flames back from occupied portions to permi; prompt evacuation and the equipment recommended has been basedon this approach. Now, as this accident (and a few others of recent date) indicated, interior cabin fire control may be more pressingthan the exterior attack. New methods and techniques will have to be developed to meet this situation. "Knowledge of aircraft exits and access points to cabin areas isvital for effective work by ground rescue and fire-fighting crews Airlines are generally willing to conduct familiarisation programmeson all their equipment and maximum advantage should be taken of all opportunities to learn aircraft design features of importanc:to those concerned with rescue and fire control." BOAC Cargo Manager Mr W. D. "Bill" Koster is to be BOAC's general manager, cargo development, following the move of Mr M. D. Morrissey to IATA (see "IATA Appoint ments" below). Mr Koster's experience with air cargo began when he was a freight clerk with Imperial Airways in 1934 Since 1965 he has been BOAC's cargo manager, Europe. IATA Appointment New positions—those of deputy traffic director and deputy technical director—have been established within IATA. The former is to be filled by Mr M. D. "Tim Morrissey, who will join the association from BOAC earl) next month, and that of technical director by Mr Arne Aagard, who has been in IATA's technical department since 1951. M' Morrissey joined Imperial Airways, BOAC's predecessor, in 1932 and was, until his new appointment, general manager: cargo. f Varig's New President Mr Erik de Carvalho (left) is elected press dent of Varig Airlines, followifl' the recent death of Mr Ru Berta. Mr Harry Schuetz has beer. elected vice-president in his place. Mr de Carvalho joined Varig i« 1955 after a number of years wi Panair do Brasil and was appoi ted vice-president in I960- Schuetz joined Varig in 1937 a had, since 1962, been vice-preside^1 in charge of the airline's inttf national division in New York.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
