Summarising from the Manchester 737 Accident Report;
Both reversers deployed and the right EPR peaked briefly at 1.32 before settling at 1.25 for approximately 5 seconds, after which reverse was de-selected on both engines at a speed of about 70 kt; only the right engine reverser buckets retracted. The reverser buckets on the left engine were able to deploy fully. However, by the time reverse was de-selected the N2 had decayed to the point where falling engine oil pressure inhibited the reverser operating system, locking-out the left engine system with the buckets fully extended…………………
The fire station crash alarm was initiated by ATC immediately the fire was observed from the tower. However, many fire crew personnel heard the bang, saw the fire and started to respond before the alarm had sounded. RIV2 and RIV1 rapidly departed and headed to where the aircraft could be seen entering link Delta, followed immediately by the Protector and J1 foam tenders. RIV2 routed via taxiway 2-North, RIV1 and the major tenders via taxiway 2. Other RFF personnel, on hearing the alarm, departed immediately to recover J2 from the hangar where it was undergoing re-painting.
The fire station ambulance, manned by RFF personnel, immediately departed for the West RVP to await the arrival of Fire Service appliances. The Airport Police also dispatched an escort vehicle to the West RVP. However, the GMC Fire Service had been alerted by the land line and told to report to the North RVP, which was in accordance with recently changed procedures.
RIV2 arrived at the scene approximately 25 seconds after the aircraft had stopped. It was positioned on the left side of the aircraft and foam was applied initially onto the left side of the fuselage and then onto the left engine. RIV1 arrived shortly after RIV2, positioned off the nose slightly on the left side, and discharged the whole of its foam along the left side of the fuselage with the intention of protecting passengers, who by then were evacuating from the L1 chute, and cooling the left side of the fuselage. RIV2, having apparently knocked down the fire around the left engine, re-positioned to the rear on the left side, discharged its remaining foam into the rear fuselage, which by that time had collapsed to the ground, and was then re-positioned clear of the aircraft.
The Protector foam tender arrived at the aircraft approximately 30 to 40 seconds after the RIVs and positioned some distance off the nose, well on the right side. It then started to deliver foam into the area of the right over-wing exit and the right rear fuselage, which appeared to be burning fiercely. Subsequently it was re-positioned twice, each time to bring it closer to the apparent seat of the fire on the right rear fuselage, before its water ran out. J1 arrived immediately behind the Protector, but was unable to position in the normally anticipated position on the nose of the aircraft because of the presence of RIV1. It was therefore positioned some 12 metres forward of the nose, slightly on the right side to the rear of RIV1, and foam was delivered down the length of the fuselage on the right side. This drove the flames rearwards, maintaining the forward and over-wing exits clear of fire. Approximately 1 minute after commencing foaming, J1 was re-positioned onto the left side in order to attack more effectively the fire in the area of the left engine and rear fuselage.
From the report ‘the rear fuselage collapsed to the ground’ less than 25 seconds after the aircraft had stopped, plus the time it took RIV1 to discharge the whole of its foam onto the fire.
From this, the report accepts that a tarmac Avtur fire, assisted by only a light breeze, will cause the back end of a 737 to drop off in (probably) less than a minute.
I believe the lethal influence of the upper reverser bucket was neglected because the FDR showed that No 1 engine was stopped, or wind-milling.
From the report;
‘In order to deflect the fire plume laterally by a distance of several feet, the exhaust efflux velocity would have had to have been significant. In fact, FDR evidence has shown that the engine ceased to deliver thrust from the instant the combustion casing ruptured (as would be expected), (would it!!!!) and therefore there would have been no active exhaust efflux from that engine.
It then says; ‘Even if the engine had been intact, but idling at the same RPM as that recorded on the FDR for the damaged engine…….’ ???
So which was it? Was the engine idling, or was it windmilling. One helluva difference in the circumstances.
At the risk of repeating myself, yet again, the fact remains that the report will have us believe that a tarmac Avtur fire, with only a light breeze, will cause the back end of a 737 to drop off in (probably) less than a minute. I think not.