ENG FAIL -- Inhibited on Ground?

[emerydc8]

That makes me wonder if it could be an operator preference.

[John H Watson]

When I played in the Lufthansa sims in the nineties, there was no such message; the LH pilot in the sim told me the first sign of an engine failure is the ELEC GEN message. -- I guess the ENG FAIL message has been added some years later, or it was available all the time and the pilot who told me that was just referring to ground operations.

There may have been a EIU software upgrade. Unfortunately, the oldest AOM in my library only goes back to '98 (and the message is listed, with the in-air requirements).

The LH pilot may have been correct in saying that the ELEC GEN is the first sign of engine failure, considering the oil pressure may take a few moments to drop below the required value to trigger the ENG X FAIL message.

[emerydc8]

I was looking at Peter's outboard engine failure after takeoff video and noticed some unusual discrepancies in the alerts compared to how I understand it. For this example, I don't know if he programmed a failure and a fire on the same engine, but the timing of the fire bell and warning beeper is puzzling:

After V1 (and still on the ground) -- ENG 4 FAIL EICAS (no beeper), followed by ELEC GEN OFF 4 (no beeper);

At 150' RA -- Fire Bell, plus red FIRE ENG 4 EICAS; and

At 200' RA -- Caution beeper.

https://youtu.be/IEtRKRb3NCk?t=1m30s

On the sim I used (ex-ANA), the fire warning bell and caution beeper are basically inhibited until 400' RA. Since Peter didn't say anything about this in the video, maybe this is normal and BA's aircraft are modified to allow fire warning bells at 150' and caution beepers at 200'? Not sure.

[John H Watson]

Perhaps an audio timing glitch in the video recording? I couldn't reproduce the 150' warning in PSX and all my manuals and the PSX manual say 400'. Even the BA Maintenance Manual says 400' (unless it has changed recently)

[emerydc8]

Either that or Peter was just using an earlier version that Hardy has since corrected. What I am seeing in PSX now is what I believe to be correct as far as the ENG FAIL caution (I haven't checked the FIRE ENG warning yet but presume it's correct too).

I scoured the Internet for probably six hours trying to find more information on this but no luck.

[Hardy Heinlin]

400 feet is not the only condition.

The inhibit is also cancelled after 25* seconds, whichever is given first.

See page 531. This is implemented since the first version; no corrections necessary.


* 25 sec after V1 for warning inhibit, 20 sec after 5° pitch for caution inhibit.

Peter's video demonstrates these delays 25/20 perfectly.

[Britjet]

I can't remember what was programmed now, I'm afraid, but I would probably have programmed the fire warning at a different point to the initial failure to make it more realistic..
I don't think there would have been a glitch in the recording, it would have been done in one take.
Peter

[Hardy Heinlin]

There's nothing wrong in the video or in PSX; the inhibits are also cancelled by timers, not just by RA. With engine failures it may take an eternity until 400 RA; in such cases the timers cancel the inhibits before reaching 400 RA.


|-|ardy


(This is now off-topic; this has nothing to do with the special ground inhibit of the ENG FAIL message.)

[emerydc8]

You're right, Hardy. So, PSX is working correctly even in situations where the inhibit timer activates prior to 400'. So the video is now off-topic.

The only question that remains is the original topic -- Why do the manuals say that the ENG FAIL EICAS, master caution and beeper are inhibited on the ground? And no one seems to have an answer.

[United744]

"Fuel not cutoff" condition is implied in the above conditions.

To me, statement 3 is correct.

[Britjet]

Just did a rather unscientific test of an engine failure in the big sim with a novice guest who was trying to loop the loop after take-off!

ENG FAIL definitely doesn't appear on the ground. Despite the rapidly increasing pitch rate today I did try and sneak a peek at the EICAS as well as save us from disaster and I think the ENG FAIL did indeed come on before 400ft but I would have to check again in somewhat more empirical conditions.

Will try to have a another go when I am in on Tues night.

Peter

[emerydc8]

Hi Peter,

Did you ever get a chance to revisit this issue? I see Hardy has it on his to-do list.

Jon D.

[Britjet]

I might get chance this weekend, Jon.
Peter

[emerydc8]

Thanks, Peter.

I guess the consensus is that you will not get an EICAS ENG FAIL until airborne if you lose an engine after 80 knots.

I would be curious, though,  to see if you would get the EICAS (and the aural alert and master caution for that matter) if you lost the engine prior to reaching 80 knots (prior to the caution inhibits taking effect). This seems to be yet another area where Boeing is unable to explain the system clearly enough. We are dealing with three different things here -- aural alert, master caution light, and EICAS ENG FAIL.

If the master caution inhibit takes effect at 80 knots, then do you get an aural alert and master caution light but no EICAS if you lose one below 80 knots (the EICAS alone being inhibited on the ground)? Or are the aural alert and master caution lights also part of the ground/air logic if you lose one below 80 knots?

[Hardy Heinlin]

I'm sure you will never get just a CAUTION light or a beeper if a caution message does not appear.

It would have no meaning.

"Look, the caution light is on!"

"Why?"

"Dunno."

:-)

[emerydc8]

True. So if you have an engine fail prior to the inhibt (below 80 knots), do you get all three or no warnings at all?

[Britjet]

I cant really test an eng fail below 80kts at the moment. It wouldn't fit with my flight sim guests. Sorry.

[Hardy Heinlin]

True. So if you have an engine fail prior to the inhibt (below 80 knots), do you get all three or no warnings at all?

You may get caution messages -- except for ENG FAIL because that is inhibited on the ground.

[Britjet]

I just tried a failure in the big sim at max weight.
The "ENG FAIL X" message appeared within a few seconds of getting airborne, although the failure occurred at 159 kts for a 167 kts rotate..I think it came on at about 30ft..

Peter

[emerydc8]

Thanks for confirming this for us, Peter.

Jon D.