Engine Fire

[rfresh737 36]

>Good question... of course you always have a fire in the engine

 

Yes, of course, but we're not talking about that fire. We're talking about the area of the engine where the fire loops are located around the inside of the engine cowlings.

 

So here is a hint: the answer is yes you can get a full on engine fire warning without actually having an engine fire (not talking about the turbine exhaust gas fire).

 

So, now the question becomes how? What could cause this trigger if not a real fire?

[Spam3d 54]

Hmm i shall have a ponder....

[rfresh737 36]

A break in the fire wire?

 

No, that would not do it and for the sake of the question, i stated that the fire detection and protection system was assumed to be working correctly  B)

[Vagabondo 23]

 

 

We'll assume the engine fire detection and protection systems are working properly, meaning they themselves have no failures. So the question to ponder is: can you get a full on engine fire warning in the cockpit and not actually have a fire on that engine?

 

Yes, a bleed air leak could be hot enough to trigger a fire warning.

[rfresh737 36]

>Yes, a bleed air leak could be hot enough to trigger a fire warning.

 

Absolutely correct. Now, can you tell from the cockpit if this is your situation? or do you have a real fire in the engine?

[vololiberista 205]

 I don't know of a 737 that has had a fire that didn't go out, though.

Manchester Airport British Airtours

http://aviation-safety.net/database/record.php?id=19850822-0

[Fabo 213]

 

 

Absolutely correct. Now, can you tell from the cockpit if this is your situation? or do you have a real fire in the engine?

 

I suppose no abnormal engine indications could tip one off. 

[Alpha Floor 237]

Absolutely correct. Now, can you tell from the cockpit if this is your situation? or do you have a real fire in the engine?

 

Maybe you could check the duct pressure in the pneumatic system. If one needle is lower than the other, that could mean there's a leak.

 

If there's a bleed air leak, maybe a Pack would malfunction or go inop and you'd get the corresponding warning for that.

[rfresh737 36]

Jaime - Bingo!! You're the man today...!!!

 

Some airlines in the US and outside of the US have their engine fire procedures written with a bleed air duct rupture in mind. Those procedures are generally written such that when the throttle is pulled back to idle, some time is spent waiting to see if the red fire light goes out. If it does, a visual check is made of the engine and if it looks ok, the crew will keep the offending engine at idle and land as soon as possible.

 

However, this is NOT the procedure that Boeing follows on this plane so don't do it! This was just a discussion to get our minds thinking on the topic.

 

I can tell you that almost every carrier's engine fire checklist is different from the factory checklist. My experience with the manufacturers is that only about 20% of the customers use the factory checklists. 80% have their own. There are reasons for this but pilot standardization is the big one. Delta at one time flew the L-1011, DC-10 and 747 all at the same time. They moved pilots around on them (one month at a time) such that you might fly the 747 one month, the DC-10 the next, etc.

 

They only had one way to secure an engine because of a fire so it didn't matter what jumbo you were flying, the steps were the same. And that's why they didn't give a hoot about how the factory did it.

 

Great thinking Jaime...!!!

[Vagabondo 23]

Maybe you could check the duct pressure in the pneumatic system. If one needle is lower than the other, that could mean there's a leak.

Ah, but one needle is often lower than the other. The inflight differential should be within 20psi though.

[rfresh737 36]

The bleed isolation valve should be manually closed to get a valid reading in this situation.

[Vagabondo 23]

This is a very interesting discussion indeed

 

I have come across some trainers who suggest troubleshooting engine fires to look for a bleed leak diagnosis. Personally I completely disagree with this philosophy unless the my company were to give specific guidance on the issue and they could only be approved by the state CAA, to do that if Boeing would have had to sign it off too - but this doesn't exist - in my world at least.

 

Because there is no such procedure for me to use and as Boeing specifically warns against troubleshooting I would just stick to assuming it is a real fire and act accordingly. The risk, however low, of being wrong is potentially catastrophic but a single engine diversion (even in busy airspace) with a mayday is not unsafe. In the real world one would have a hard time justifying their actions if they deviated away from standard non-normal handling if the application of those non-normal procedures does not put the aircraft at greater risk.

 

Well, it works for me

[rfresh737 36]

To be clear, the US carrier pilots, in my experience, would not be troubleshooting any malfunctions. Way, way too much legal exposure to do that. They just wouldn't do it. They will always call for the checklist and follow that...period.

 

However the checklist is written, you can be sure it has to be approved by the manufacturer and then the FAA to make it into the QRH.

 

Having said that, there have been exceptions, not related to engine fires, and two come to mind:

 

(1) Long ago, a Pan Am 747 was departing SFO on a clear day. Captain Calvin Dyer was at the controls. They took off and the runway was too short and he had to rotate before Vr and as he pulled the nose up, the tail came down on some runway piers holding up the runway over the water and they lost 3 of their 4 hydraulic systems. The problem was they had no procedure for a triple hydraulic failure. Boeing thought the odds of losing 3 out of 4 was too great and they only had a single and double hyd failure in the QRH. The crew was on their own as to how to handle the triple failure and of course had no choice but to handle it as best they could.

 

They dumped fuel for almost an hour and came back in to land, flying on one hyd system. News cameras were in place by that time to record the landing. The flare was weak because each elevator (4 of them) was powered by each hyd system so Calvin only had 25% of his force to flare...only one elev deflected up so he hit rather hard and bounced and came back down.

 

When he went into reverse, he only had it on one side and it forced him off the side of the runway. In a vain attempt to stay on the runway, you could see the split top rudder deflected fully but it wasn't enough to stop the veer to the right. The plane stopped ok and everyone started to evacuate.

 

Two happened as a result of that accident that day: (1) Calvin Dyer never flew again as he failed to ensure that the last minute runway change was long enough to take off from (it wasn't) so he paid the price and lost his job and (2) Boeing and every other jetliner manufacturer that had a jet with 4 hyd systems made sure there was a triple hyd failure checklist.

 

(2) One of the A-380 middle east operators had that massive engine explosion that ripped off part of the wing and poked big holes in surfaces of the wing, had so many emergency alarms, lights and bells in the cockpit, they couldn't manage all of it. There were so many malfunctions, many were caused from electrical wires being cut by the explosion so while the cockpit indications showed some systems and components failed, they were in fact working but the crew didn't know and couldn't tell.

 

They experienced multiple failures that were never supposed to happen thus there was no checklist for them all. There were 5 pilots working over time in the cockpit to manage all the failures as best they could...without a checklist...and they made it back safely. It was only after fully understanding all the real failures they had and there were many, they realized how close they came to crashing. They just made it in by the hair on their chins!! But as in the Pan Am case, the A-380 crew didn't have any choice...they had to troubleshoot and use their systems knowledge to best handle the malfunctions at the time and hope they were right.

 

I can't remember all the details of reading about the avionics software, but the failures were so massive, I think the software was over loaded and was displaying incorrect things on the screens. Airbus NEVER expected that many failures with the software so it was never tested for that many. What a mess and nightmare that flight must have been for the crew.

[Vagabondo 23]

Yeah, troubleshooting is needed occasionally, but  most usually due to multiple systems degredation forcing a difficult decision as per your Pan Am example. I don't know what the QRH was like back then, but these days there isn't a triple hyd failure QRH as such, the QRH just lists the system degradation to be expected for each system. Perhaps if Captain Dyer had that information easily to hand he would have realised couldn't make a safe landing and would have diverted elsewhere (conditions permitting).

 

Regarding the A380, are you in fact referring to the Qantas A380 that experienced uncontained engine failure and landed in Singapore as I'm not aware of Emirates having anything other than IFSDs? If so, it was and amazing event and the crew did a terrific job and should be held up as an example of excellent CRM. There wasn't a systems overload as such, and the crew did actually work through each checklist. The problem was the ECAM, due to multiple failures, was providing contradictory actions between different checklists. They had to lists all the items and work through the contradictions separately to develop a plan on how to action the checklists. Eventually they completed to work and calculated they could land with barley any runway remaining. Even after landing, with one engine being uncontrollable it took hours of dousing by the firecrew to shutdown the engine!!

 

What was so significant about the Qantas incident, was not just the unusual and complex nature of the problem, but how all the crew were effectively involved in the process of safe return. The most difficult decision was whether to evacuate on the ground or keep the passengers on board, taking into consideration the engine that wouldn't shut down and a fuel leak near very hot brakes due to the maximum effort landing. What an achievement not to make a single significantly bad decision! B)

[PhantomTweak 3]

The possible causes and indications are the same for the F-14 and FA-18 aircraft. If you get a fire indication, engine to idle, secure the bleed from that engine. If the light goes out, throttle as needed but keep the bleed from that engine off, land as soon as feasable. If the light stays on, get inspecion from wingman and if flames observed or temps in the engine increasing, Throtle-->cut-off, Fire handle PULL. The fire handle also triggers fuel cut-off valves, as well as discharging one of the Halon bottles. If the fire doesn't go out or gets worse, pull again to trigger second botle. If fire persists....EJECT!

 

That's a very abbrerviated version of the Natops proceedures, but covers the point, at least, that the proccedures, right up to EJECT, are very similar for the military birds and civilian ones...

 

Good post, ty to all for their inputs!

Pat☺