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B737NG engine fire just below V1

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B737NG engine fire just below V1

Old 23rd Jun 2007, 13:12
  #61 (permalink)  
 
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Personally I think doing it at all is pushing most peoples' luck too far from some of the handling skills I have seen.
Kind of sums up my aviating credentials in one succinct phrase TYVM
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Old 23rd Jun 2007, 13:20
  #62 (permalink)  
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At ease, Sir! I never flew with you
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Old 23rd Jun 2007, 13:31
  #63 (permalink)  
 
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Choice of death or give it a go, give it a go.
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Old 23rd Jun 2007, 13:59
  #64 (permalink)  
 
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Given that we only do bi annual sim assessments there is only so much that can be covered and while you may get to have a go at a turnback/short pattern circuit you certainly won't get to be practised at it.
And that is one of the problems. We spend countless simulator hours ticking the scheduled boxes, engine failures at V1 time after time, year after year, in addition to happily playing at actors and actresses during straight and level LOFT or whatever the latest terminology has it.

CDU buttons are pressed with great aplomb and the wonderfully reliable automatic pilot is used most of the simulator time. Yet hands on practice is rarely made available for the rare events that have really happened to other people. The events that require first class manual handling skills. For example let's include such things as close-in very low level circuits, dead stick landings, full blooded GPWS terrain warning and instant reaction pull-up, flight control failures where only the engines are left to give pitch and roll, the really nasty unusual attitudes and recovery technique, ditching technique in IMC - and other events I am sure readers can envisage.
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Old 25th Jun 2007, 18:28
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Rainboe's last post touched on a point I made some years ago which was not widely distributed in the pre-pprune era!
I entlitled my letter to the editor of Flight, Attitude at Impact. I am unsure if it was printed as I didn't and still don't subscribe to the magazine.
In brief, the point of the letter was that we pilots are programmed to behave in certain ways in certain conditions due to our SOPs and our sim rides every six months.
At the risk of a fatwa in my criticism of Captain Haynes and his crew, I mentioned the DC10 crash at Sioux City and questioned the decision of the crew to attempt to land the aircraft on the runway. They had proved to themselves that they had a very limited amount of control over the aircraft. What did they think when they decided to try to land on a runway, 8000 feet long and 145 feet wide? They had the whole of Iowa to land on, a flat and fairly hard landscape, I believe.
Bear in mind that when they were cleared to land, Cpt Haynes replied, 'You want to make it a runway, huh?' I think he was a little late in considering the option of landing elsewhere.
Their thought process was inbuilt over many years of flying experience. My contention is that this subconcious wish to land on or return to a runway is misguided. Our attitudes need to be altered to accept that there will be situations where landing straight ahead is a far safer option than trying any 35 degree turns on one engine with an uncontained fire, or no flight controls, come to that.
I know this thread is not strictly dealing with this issue but it seems like a good place to bring it up!
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Old 25th Jun 2007, 20:36
  #66 (permalink)  
 
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If I'm gonna crash land then you can sure as hell bet that I'd rather do it at an airport where the Emergency Services are on hand within a minute or so as opposed to a field in the middle of Iowa where, if you're lucky, you would get farmer Joe and his trusty tractor on hand to give CPR and pee on your fire a week next Tuesday.
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Old 26th Jun 2007, 08:18
  #67 (permalink)  
 
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My point exactly. Try to land your uncontrollable aircraft and roll it on its side, tear it apart and burst into flames killing 110 passengers and 1 crew or gently lower it onto the mud and let it slide in one piece to a stop in the middle of the fields.
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Old 26th Jun 2007, 12:00
  #68 (permalink)  
 
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guest27 has posed a very interesting question; namely.

Engine fire just below V1, is it always correct to reject take off?
A modern jet airliner is designed to withstand and contain an engine fire during any phase of flight. This includes from start to taxi, takeoff, cruise, descent and landing.

Considerer for a moment, what is the real world difference between an engine fire at 5 seconds before V1, 5 seconds after V1, during the climb, during the cruise (especially over the mid-Pacific where one might be 3 hours from any possible landing), or during descent etc?

The design engineers have to allow for the case of engine fire and in particular isolating the damaging effects of heat from critical structures for a period of time until the source of fire can be isolated, contained and extinguished. How can anyone say that a fire at V1 is somehow more time critical than a fire in mid-oceanic cruise?

Just going back one step, we all know that a fire can only exist with all three critical items being present; that is, a source of fuel, oxygen and heat. Without one of these elements, fire is impossible. Once an engine is secured, fuel, hydraulics, electrics have been cut off. Next, the extinguisher gases will deplete the oxygen.

Typically, engines that do catch fire continue to produce normal or at least significant thrust until they are secured. This thrust is usable depending on the situation (climbing to 400' agl for example) until the engine is secured.

At speeds close to V1, an aircraft has more potential to go flying than it has the ability to stopping. Indeed V1 for a particular situation may mark the last possible moment in time where the aircraft can be brought to a stop if all the prerequisite retardation devices work and the crew performs their duties precisely. Max/heavy weight takeoff aborts at V1 will always involve wheel fires and possible injuries to pax during any subsequent evacuation.

Your airline standard operating procedures will dictate what your actions should be in the case put forward by guest27. Nonetheless, if you are a Commander or aspiring to become a Commander, it is your personal responsibility to ponder the question that is on the table, in an unemotional and objective manner. Quite apart from the Coroner's Court, you may have to live with your decision for the rest of your life.

Engine fire just below V1, is it always correct to reject take off?
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Old 26th Jun 2007, 13:45
  #69 (permalink)  
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As the question stands....I'm a YES. I cannot think of any circumstance when I would not. Fire and humans don't mix. Fire and daralumin structures doesn't mix. What is your V1 for? You haven't got decision thinking time. It should be automatic:.....fire....below V1...stop.
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Old 26th Jun 2007, 14:23
  #70 (permalink)  
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Quite apart from the Coroner's Court, you may have to live with your decision for the rest of your life.......
Flexible Response,
actually my concerns are exactly the brakes' efficiency in some specific scenario (fire always involved?) and the predictable pax evacuation in case of RTO procedure.

Many colleagues are contributing with their experiences but I still have some doubts if is better to reject always.
Thank you all,

Guest27
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Old 26th Jun 2007, 22:17
  #71 (permalink)  
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or gently lower it onto the mud

.. if we are talking about Sioux City ... if they had had anything like enough control over the beast to do anything predictable with it ... mud, runway, or whatever ... then they would likely have got away with no consequential damage and no injuries during the landing.

As it was, they had an aircraft which was extremely marginal in respect of any level of control ... Lady Luck helped a bit (except for the phugoid pitch down on short final) ... but full marks to the dogged determination of the crew on the day ..
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Old 27th Jun 2007, 07:53
  #72 (permalink)  
 
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Taken from FAR PART 25 section 2 - abbreviations and symbols

V1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance

Taken from FAR PART 25 section 107 - takeoff speeds

(a) V1 must be established in relation to VEF as follows:

(1) VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant, but may noy be less than VmcG determined under Sec. 25.149(e)

(2) V1, in terms of calibrated airspeed, is the takeoff decision speed selected by the applicant, however, V1 may not be less then VEF plus the speed gained with the critical engine inoperative during the time interval between the instant at which the critical engine is failed, and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot's application of the first retarding means during accelerate stop test.

_________

So for those of you who still want to continue before V1...
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Old 27th Jun 2007, 10:43
  #73 (permalink)  
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So for those of you who still want to continue before V1..

ah .. but one still has the little problem of lining up the black and white of the idealised and repeatable certification animal with the sometimes quite different real world beast.

As the aviation world is moving these days .. one needs an holistic risk minimisation approach to one's decision making .. most of the time the real world matches the ideal sufficiently (or with sufficient margin) that the decision is programmed and easy .. sometimes it is not quite so simple as overlaying the real with the ideal.
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Old 27th Jun 2007, 13:04
  #74 (permalink)  
 
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john_tullamarine,

Very nicely put, Sir!

Best regards,
Flex
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Old 27th Jun 2007, 14:09
  #75 (permalink)  
 
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I try again...

quote: V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance

No time to think - just act. Hence the repetitive practise in the sim...
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Old 27th Jun 2007, 15:37
  #76 (permalink)  
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ah .. but one still has the little problem of lining up the black and white of the idealised and repeatable certification animal with the sometimes quite different real world beast.

As the aviation world is moving these days .. one needs an holistic risk minimisation approach to one's decision making .. most of the time the real world matches the ideal sufficiently (or with sufficient margin) that the decision is programmed and easy .. sometimes it is not quite so simple as overlaying the real with the ideal.
Well it might be very nicely put, but what the hell does it mean? Is it Yes or is it No?
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Old 27th Jun 2007, 16:45
  #77 (permalink)  
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It either means it is a definite maybe or he's been at the Fosters
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Old 27th Jun 2007, 18:54
  #78 (permalink)  
 
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No time to think - just act. Hence the repetitive practise in the sim...


Right on, unfortunately on the internet chats, pilots like to write about what they think should they be in a situation where they have no time to think.

I guess it's a macho thing
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Old 27th Jun 2007, 21:05
  #79 (permalink)  
 
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It's not black and white. Flying seldom is.

In most cases, it is a stop.

Now consider;

-1600-1800 meter runway.
-Runway is contaminated, mixed snow/ice.
-You use the reported braking coefficient.
-Computer has calculated your max take off weight down to the kilo.
-You are at max weight.

You know that;

-Braking action is measured at 60 km/h, not the required 90 km/h. It's not safe to drive faster.
-Braking action measurement is not an exact science.
-You use the average braking action of the far 2/3 of the runway.
-Conditions vary.

The fire alarm goes off at V1 minus 5. Both engines produce full thrust.

Do you stop?

Are you able to?

Now, as our Danish friend pointed out;

"V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance."

But he is talking about engine failure, not engine fire. An engine fire may be an engine failure, but it doesn't have to be. With 2 engines running you will have no problems (lifting off) if you continue.

If you continue on one engine, you will still lift off before the runway end. You will not clear it with the required 35 ft, but you will still be airborne.

I realise most of you never see this scenario, but some of us do. We can not afford to treat a situation like this like robots.

I don't feel very macho for saying so.
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Old 28th Jun 2007, 00:45
  #80 (permalink)  
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.. the last few posts represent where the discussion ought to be leading .. one of putting sensible and logically contrary viewpoints for the purpose of discussion and reflection.

Pilots need to have an idea of the real problems as opposed to SOP cant. Note I am not trying to belittle the SOP approach to things as such rigour, on the very great majority of occasions, provides us with a high probability of a successful outcome. The discussion ought not to be centred around what one might do on the day but, rather, examine the ins and outs of what should be considered in the decision making process which goes into the pre-roll briefing etc.

Some thoughts ...

No time to think - just act. Hence the repetitive practise in the sim...

This approach works well most of the time. However, we need to accept the consideration that there will be situations where the highly automated, rule-based, reaction may just not provide a desirable outcome. As is often suggested, it is not about absolutes .. it is about probabilities and the need to load the dice as much as one can in one's own favour ...

In critical circumstances, where the ideal is blurred by the reality of the real ... precisely this desirable skilset may just be the thing which puts the aircraft into harm's way ?

but what the hell does it mean? Is it Yes or is it No?

It means, for this question, that there are three domains of interest ..

(a) low speed black and white .. the probability of a successful outcome is loaded to the SOP stop case .. he who keeps going would be looked upon with critical gaze. This continues to be the case approaching V1 if the field length clearly is non-limiting with a comfortable margin ..

(b) an ill-defined, very greyish, area approaching V1 in limiting circumstances .. each case needs to be assessed separately. What is the best decision ? .. hard to say as the boundary conditions which constrain the decision making process may vary considerably.

(c) high speed black and white (assuming there is no secondary consideration arising which precludes flight) .. similar to (a) but loaded to the GO case.

(a) and (c) generally are easily seen as being rule based and programmed

(b) ... ? it depends ...

or he's been at the Fosters

.. only if there's nothing else on offer ... Hunter and Guinness for this lad by preference ..

We can not afford to treat a situation like this like robots.

That's the point I am trying to get across ...
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