Evacuation - with fire outside

[IGh]

External (pool) fire? Difficult to generalize Optimal Action

Problem posed in top slot:

"... the F/A instructing passengers sitting ... overwing exit rows ... if there were signs of fire outside the aircraft, do not open the overwing emergency exit.... got me thinking ... smoke inhalation...."

There are many cases to study (see reviews from Dick Hill and Dave Blake, at FAA's Atlantic City Research Center).

There's no correct answer that works well in all the earlier exemplar cases -- evac' is the usual response. Maybe ChinaAir B737 at Naha Aug07, is the latest exemplar in which evac was preferable.

Remember -- The pilot will likely have even less information than the passenger sitting next to a window in the aft cabin, as can be observed in review of cases where the pilot continued taxiing the aircraft while passengers agreed that they wished to evacuate:

Pacific Western Flt 501 / 22Mar84 , B737-200 C-GQPW, Calgary Alberta; aborted takeoff after engine failure at 75 Kts; Uncontained failure of the left engine's 13th stage compressor disc. Wing fuel cell penetrated by debris, MAJOR FUEL-FED EXTERIOR FIRE, pilot delayed evacuation even after confirmation of fire. Passengers initiated evacuation, all 119 sob's evac'd & survived.

T/O @ 0742 MST Rwy 34 from C-1. About 20 seconds into T/O roll pilots heard loud "bang" then aircraft had slight veer left. RTO. MISPERCEPTION: Pilots thought tire had burst. Slowed, taxied clear of rwy @ C-4; Pilots noted left N1 = 0%, and left generator failure.

Time from disc failure to evacuation finished was 4 or 5 minutes.
23 Seconds after RTO initiated, F/O called to Tower "Clear of Rwy."
45 Seconds after RTO initiated, Cockpit Door was opened in response to knocks, F/A entered and asked if they had blown a tire, and then F/A stated ". . . fire at rear of aircraft . . . back of left wing." CVR recorded brief sound of fire bell and Chimes from F/A to Cockpit Call System; F/O called Tower and asked confirmation of fire.
At One Minute +Two Seconds Twr called back confirming fire; F/A-Purser told pilots "whole left back-side [wing] is burning."
At One Minute +11 Seconds Captain told F/A to "prepare" for evacuation; discharged fire bottle to Left Engine; told Twr to send emergency equipment; Tower replied that crew best stop the aircraft at their present location.
At One Minute +33 Seconds Tower told crew that there were flames on the left side.
At One Minute +36 Seconds Fire Bell sounds continuous; F/A reports "bad at the back." Capt discharged second fire bottle, told F/A to again "prep" for evacuation.
At One Minute +40 Seconds Captain finally STOPPED the aircraft, pilots executed steps in their Evacuation checklist.
At One Minute +55 Seconds F/A's finally initiated their evacuation procedures; fire melted windows along left side and heat and smoke entered aircraft; smoke in aft cabin worst.

Fire consumed substantial portion of aircraft. Left Engine fire damaged, Engine Case and Nacelle perforated at the One O'clock (as viewed from rear) upper I/B position. Lower Wing perforated (I/B & in-line with hole in nacelle & 13th stage compressor), skin penetrated, fuel cell broken (Hole in under-surface of wing tank). A segment of engine's disc, 3" by 17", missing; found on Rwy 1300' from start of T/O roll. [Improper stator repair, not IAW PW overhaul manual; disc failure included fatigue cracking.]

Pieces of aircraft structure and left engine were later found on Rwy and Twy; TRAIL of raw and burnt fuel residues, & globules of melted aluminium had fallen from left wing; trail continued to final resting position of aircraft. "3-D Fire": elevated fuel source, a running (falling) fire, and ground pooling.

Problems with Emergency Equipment: nacelle and wing blocked access of foam cannons (positioned atop fire vehicles) to fire source (under I/B wing).

AGARD Discussion: (CWK) Manchester, Calgary, and Ryhad mishaps included an aircraft on fire which the pilots taxied off runway onto a taxiway, with detrimental results; delayed Pax evac, and reduced maneuvering space for emergency equipment (Calgary fire trucks stuck in mud just off taxiway). Hidden fires: external or internal (CVG)?? [Pac West, see also 22Aug85 at Manchester.] ["The Final Call" S BARLAY; 157. AGARD's "Aircraft Fire Safety".]

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Just another example of evac' with an EXTERNAL fire:

TWA, July 30, 1992. A TWA L-1011 aborted a takeoff, touched-down hard and ruptured a wing fuel tank (aft Spar fracture dumped fuel onto hot brakes) . A large fuel fire engulfed the aft portion of the aircraft. Fire and smoke entered the cabin through the aft doors during the evacuation. All 292 occupants exited through 3 forward exits in approximately 2 minutes.

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There are many other EXTERIOR fire cases to consider, usually prompt evac' was the best response (For a Tire/Brake fire a better plan would be to get the ARFF into the Wheel Well area and stop fire. But Pilots just can't verify that ARFF is actually inside the Wheel Well with their fire stopped, so UNCERTAINTY suggests evac'. External cameras might reduce the uncertainty.)