NB NO 747 experience...

Whilst I resisted calls for 'Boeings head' on the Schipol Radalt accident, and given that as usual we are all working here on 'hearsay', I would question why B did not think about this 'failure' and its consequences above V1. Assuming it happened above V1 as stated, it left the crew with no real options but to continue with a crash extremely likely. The ensuing rotation must have been eye-watering! The call for inhibition of the LED retraction with more than xx power set is very strong.

If this failure should happen below V1 but at high speed............ I guess the T/off emergency briefs will be changing until mod action is in place.

A think that you will find most 747-400 drivers will now call stop for a thrust reverser amber, with or without any other cue (swing etc).

Ex JNB at about 350 tonnes TOW, the V2 will be about 174kts with V1 about 155 and Vr high 160's at a guess, take off roll about 65 seconds and 4000 metres.

If I had an unlocked warning on the T/R(s) that maintenance had been working on, I would not assume it was spurious!!!

tyro

I believe that the inbound crew had reported a failure of the autospeedbrake on landing. The outbound crew would probably have been faced with an engineering item saying that some 'tests as per Maintenance Manual x.y.z carried out, and system satisfactory.'

They would not know what specifically had been carried / have reason to suspect that the reversers had even been part of that procedure and would have taken it as read that the engineers had done everything as per the book.

You may well be right, TopBunk, but I was responding to a statement by Pinkman about the thought processes of a crew who had been fully briefed about maintenence actions, which then transpired to have not been correctly done...

Rectification of which presumably would not involve the LED and T/R....

TopBunk.......... correct!
TyroPicard............ also correct!

Pinkman - there'd have been no handover after the maintenance. The aircraft lands in the morning and leaves in the evening. Probably wasn't even the same engineer on duty when the outbound crew accepted the aircraft.

I think they might have scribbled a little note in the log.

Didn't work the 747, does reverse thrust pop the speedbrake lever up?

Please tell me that you're pulling my leg. Surely when a new crew accepts an aircraft they get briefed on any aircraft performance issues on the inbound leg, any maintenance actions, MEL items etc? It shouldn't matter whether the aircraft has been on the ground two hours or twenty hours or how many shift changes there have been in between.

I cannot believe the crew did not know about any maintenance, whether or not it involved the reversers and whether or not the reversers were actually deployed on the ground per the earlier post. This goes back to my earlier question about whether all or just 1 & 4 engines were firewalled. Why would you firewall the other two engines if you seriously believed the reversers actually had deployed?

<A think that you will find most 747-400 drivers will now call stop for a thrust reverser amber, with or without any other cue (swing etc).>

Not after V1 I hope!!


and yes the crew would have known of any engineering input as soon as they reached the aircraft and examined the tech log.

The tech log will tell you what the speedbrake defect was on landing and whether or not the engineer cleared that defect. If they want to know the procedure used to fix the defect they can look in the MEL. If Pinkman thinks that there'll be an engineer waiting at the aircraft waiting to personally brief the flight crew on what was done in detail then he'll be disappointed.

The maint manual will tell how to invest/test/fix. (FIM)
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The MEL may tell you a lock out proc or similar.
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Trying to read between the lines here, systems may have been tested using APU or ground cart air, duct press may have been unstable due demand of Rev's and demand hyd pumps(ADP's) due spoiler ops.

The above may lead to Rev's being stowed and locked, but just not at the max closed/near position(prox) a prev post by SMOC is about right, Hi power and a few bumps on the T/O could be just enough for prox to be far.

Remember, in normal operations, 4 engines running = good duct px for Revs and demand pumps(ADP's), plus 4 EDP's giving loads of hyds for spoilers.
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The following link is a good slide show..
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Fc744 Flightcontrol
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I guess I'm disappointed
 

I guess I'm disappointed. In my industry (fuel refinining) where equipment fails at any time of the day/night, is fixed, things catch fire and go bang causing the same kind of loss of life as your average aircraft disaster we personally brief EVERY shift, EVERY handover, have tech logs, defect logs, etc. Its very formal.

Desk Jockey: Yes engines 2 and 4 in rev will auto deploy speedbrakes - Other conditions also need to be met i.e a/c in ground mode. (To overcome the lever lock solenoid)

Isn't that something to do with the landing gear lever? :}

Not according to the schematic!

Yes, there is also a "lever lock solenoid" on the speedbrake schematic.

However, this relates to the Flight Detent. It has nothing to do with Autospeedbrake ops ;)

CHeerS
NSEU

It always amuses me to see everyone picking over the bones of these incidents in great detail, being wise after the event.
I thought that's what official investigations are for?


Having heard what actually happened from those VERY close to the event, I assure you it relies on pure instinct and all those hours of flying you've managed to accumulate over the years. So when the details are finally published, it would be nice to see all self appointed experts return to this thread and give the crew all the credit they will undoubtedly be getting.

And perhaps put themselves in the position of those who found themselves in a situation way outside anything ever they've ever experienced or been trained for.

Nevermind

If thats the way you view PPrune, then the forum isn't for you. The forum is for people - nominally pilots - that view what they do as more than a job, have impatient, inquiring, minds, and are passionate about continually learning from mistakes, incidents, and near misses to improve their own performance. It includes not just pilots but some of the finest technical experts in other aviation related areas including ATC, engineering and maintenance, airframes, aerodynamics, runways, fuels, aviation medicine, aviation law, and much more.

The accessibility of the forum means that you get a proportion of posts from idiots, poseurs, and tosseurs, but the moderators weed much of it out. I don't see anyone on this thread being wise after the event. I don't see anyone on this thread criticising the crew or setting themselves up as self appointed experts.

What I DO see is lavish praise and huge amounts of respect for that crew as people on this forum try to understand what happened and why.

Read post 97 on this thread from 4PWs and tell me how you get to where you are from there...