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Fuel cross feed after fuel leak.

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Fuel cross feed after fuel leak.

Old 4th Nov 2019, 20:27
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Fuel cross feed after fuel leak.

Gentlemen.
In my previous airline, in a sim check, there was a fuel leak. The first thing the QRH says, is to stop cross feeding, if you are doing so.
This is pretty good advice, since- if you are feeding both engines from the side that is leaking, there's a chance that it's all going to go quiet once that tank runs dry.
So, after the QRH had been auctioned, I used the cross feed to keep both engines going, and we landed on two.
Bravo, said the instructor. First guy to land with both running since we started this sim scenario.

In my new airline, guess what? Same situation.
So, after the same old QRH- same type btw- Embraer 190, I happily switched the crossfeed to keep both the engines running, but this time I was criticisedin the debrief for doing so.
You should have just done a single engine approach, said the instructor- that's why we practise it in the sim he said.

In my own turn, I said he must be nuts. If he was flying his own family in a Seneca, and found himself in the same situation, would he really prefer a single engine approach, and possible G/A, or would he keep them both running from the tank that had fuel?

Any thoughts, fellow pruners?
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Old 4th Nov 2019, 20:52
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I'm not familiar with the E190. However, in general, once QRH procedures are completed, you should manage the failed system and the airplane to the best of your knowledge and capability. If there is no QRH prohibition on using crossfeed, and you are confident you have isolated the leak and can proceed without re-introducing it, I would go with preserving 2-engine operation.
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Old 4th Nov 2019, 21:16
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Iím sure your manual has something similar to this:

ß121.557 Emergencies: Domestic and flag operations.

(a) In an emergency situation that requires immediate decision and action the pilot in command may take any action that he considers necessary under the circumstances. In such a case he may deviate from prescribed operations procedures and methods, weather minimums, and this chapter, to the extent required in the interests of safety.

If youíre sure youíve isolated the leak, nod, smile and go about your day.
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Old 4th Nov 2019, 22:38
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Not really enough information to answer specifically, and I definitely am not familiar with the E-190 or the QRH procedure, but here are some of my general thoughts.

First, did the QRH procedure actually isolate the fuel leak? If not, then reinstating the cross feed may (literally) piss away additional fuel. This might actually be okay if you have more than enough fuel to get to your point of landing, but may leave you short otherwise (for instance, Air Transit Flight 236, August 2001). Second, if you are actively leaking fuel as you land, it may create an additional hazard particularly if the leak is in close proximity to a running engine. Even if you shut the engine down right after touchdown, it will still be hot and could potentially ignite any fuel vapors in the area. Finally, there is the issue of lateral imbalance. Depending on the exact scenario, cross feeding may hurt or help maintain the imbalance within limits.
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Old 4th Nov 2019, 22:56
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Unrelated cause, but, imagine how much better the ATR accident in Taiwan might have turned out if they hadn't hurried to shut down the engine.
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Old 5th Nov 2019, 02:49
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I don't know the EMB-190 QRH, but I was involved in the evolution of the Boeing fuel leak procedures over the last 30 years, and the system architecture is effectively the same with respect to this issue. The reason they want you to stop any crossfeeding in progress is to allow you to determine whether the leak is in the left or right engine fuel system. (Large leaks are almost always from the plumbing, not the tank itself.) Once you have verified a leak on the left or right side by comparing fuel flows and watching FQIS dropping over a period of time, the procedure (at least on the Boeing airplanes) is to shut down the engine on the affected side to stop the fuel loss primarily to preserve range, and also to reduce the risk of fire. You then crossfeed as needed the same way you would for any other engine shutdown. Depending on the mission, the fuel leak rate, and where you are in the mission, you may need all of the fuel in both mains to make your destination, alternate, or diversion airport on your remaining engine.

So, Nomad2, you were correct that you don't just keep the crossfeed closed, but the second instructor probably expected you to shut down the engine on the affected side, which I suspect is the QRH procedure. Keeping the leaking engine going and balancing into the leak is what led to the A330 dead-sticking into the Azores. This link tells that story if you aren't aware of the event.

https://lessonslearned.faa.gov/ll_ma...=73&LLTypeID=2
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Old 5th Nov 2019, 04:31
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Originally Posted by Nomad2 View Post
Gentlemen.
In my previous airline, in a sim check, there was a fuel leak. The first thing the QRH says, is to stop cross feeding, if you are doing so.
This is pretty good advice, since- if you are feeding both engines from the side that is leaking, there's a chance that it's all going to go quiet once that tank runs dry.
So, after the QRH had been auctioned, I used the cross feed to keep both engines going, and we landed on two.
Bravo, said the instructor. First guy to land with both running since we started this sim scenario.

In my new airline, guess what? Same situation.
So, after the same old QRH- same type btw- Embraer 190, I happily switched the crossfeed to keep both the engines running, but this time I was criticisedin the debrief for doing so.
You should have just done a single engine approach, said the instructor- that's why we practise it in the sim he said.

In my own turn, I said he must be nuts. If he was flying his own family in a Seneca, and found himself in the same situation, would he really prefer a single engine approach, and possible G/A, or would he keep them both running from the tank that had fuel?

Any thoughts, fellow pruners?
I can talk about Airbus. After the fuel leak procedure has been run and the fuel leak has been stopped only then cross feed can be considered. This can only happen if the leak was from one of the engines and the procedure would have asked the engine be shut. Now if you need the fuel from dead side to reach destination you can use the cross feed. Otherwise for handling purposes balancing is not required. If the leak was from the wing tanks or center tank then the engine is to be kept running till it flames out or aircraft is landed but cross feed is to be kept shut.

Last edited by vilas; 5th Nov 2019 at 05:00.
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Old 5th Nov 2019, 06:20
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Thanks for the replies, guys.
On the Embraer, one line in the 'one engine inop approach and landing' QRH, is fuel crossfeed OFF.

I believe this is legislative In basis, and not for any technical reason, but it's still in there.

Clearly, we couldn't reset it to OFF as that would result in an engine shutting down while on final approach.

In our sim scenario, the contents of one tank simply reduced rapidly to zero- a big leak- so all the fuel on one side was quickly lost, and the other side was unaffected.

I maintain that the purpose of the crossfeed is so you can run both engines from one side, so why not do so?
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Old 5th Nov 2019, 08:18
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Nomad2
You may not have considered whether the leak was identified from the engine or the tank. Both checkers could be right. In the first case the leak may have been from the tank so you decided correctly to keep it on and proceed to diversion land on two engines or if it flames out then on one. In second case the leak was from the engine and it should have been shut. Keeping it on in this case was incorrect. Also after confirming leak has stopped cross feed should have been used to give you access to dead engine side fuel.
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Old 5th Nov 2019, 10:32
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In some scenarios, you need to preserve all the fuel you can get. Even if it means shutting one, keeping the cross-feed open and transferring the content of the leaking tank to the opposite engine while you still can.
In some scenarios, you may wish to keep both engines running. Even if it means with one wing already empty, transferring to that engine from the opposite good side at the expense of letting the oversupply drain out of the defective tank.

If the procedures for one of the above would be mis-applied, (that's what human elements are for), the outcome might be fatal.

Without knowledge of the E190 (myself on an ancient type), I think there will be only one fuel leak NNC. That NNC, as written, will typically need to provide one-solution-safe-for-all drill (typically fuel preservation)

After you have applied that NNC there might be room to apply core system knowledge and sound judgement. But that is very different from the goal of the checklist's designers and people who approve such. One also might make a very big mess of it.

Nomad2 I think the relevance to your second experience is not with Air Transat (they did not understand the problem until too late), more with Air Asia (unauthorised reset).

See, SIM sessions have a plan and the good ones have a training objective behind them. To execute a correct NNC properly and stick with it is a desirable skill, maybe that is what the instructor was authorised to train you that day. Perhaps he needed you on one engine for the remainder of the exercises (sure, there are buttons for that at his station).
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Old 5th Nov 2019, 13:12
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In FUEL LEAK procedure the first action after leak confirmed is:
LAND ASAP in red. So considering leaking tank quantity as not available a suitable airport should be chosen as diversion and aircraft headed towards that. Everything else comes after that. Whether on one engine or two engines will be guided by the procedure.

Last edited by vilas; 5th Nov 2019 at 13:35.
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Old 6th Nov 2019, 10:41
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Originally Posted by Nomad2 View Post
Thanks for the replies, guys.
On the Embraer, one line in the 'one engine inop approach and landing' QRH, is fuel crossfeed OFF.

I believe this is legislative In basis, and not for any technical reason, but it's still in there.

Clearly, we couldn't reset it to OFF as that would result in an engine shutting down while on final approach.

In our sim scenario, the contents of one tank simply reduced rapidly to zero- a big leak- so all the fuel on one side was quickly lost, and the other side was unaffected.

I maintain that the purpose of the crossfeed is so you can run both engines from one side, so why not do so?

I havenít flown the E190 in very long so I donít have any aircraft specific advice for you. However judging from what you say, (ie quickly lost all fuel on one side ) I suspect this leak is from the engine. A tank leak would not be so rapid and likely very hard to detect.

For this reason, the crossfeed should be kept closed while the fuel leaking engine is still running. Otherwise the engine will pump the other tank dry aswell. Once the engine has been shutdown and secured and a leak no longer exists, opening of the crossfeed valve can be considered, if any usable fuel is available on the affected side. I would probably resist opening the crossfeed even in this scenario unless i require more fuel to reach an ERA.
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Old 6th Nov 2019, 13:36
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I maintain that the purpose of the crossfeed is so you can run both engines from one side, so why not do so?
The purpose doesn't include fuel leak. Also simply switching on Xfeed doesn't do anything unless you switch off fuel pumps from one side. If you did that on the leaking side then you will only end up loosing fuel from non leaking tank. And you did it on the non leaking side the leaking side engine will flame out early. Just follow the check list. Don't device a new one.
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