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Scenario discussion

Old 15th Nov 2012, 06:19
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Scenario discussion

Hello. I would like to discuss the next scenario which isasked during Capt upgrade training:

You are dispatched with MEL as one of the engine fire loopsinop. During cruise a second loop goes inop, without fire warning or any otherindication except pilot awareness. Leaving you basically without fire detectioncapability inflight on one of the engines?

What would your considerations. Would you continue ordivert? Why? What would you do with the engine?

And to conclude please add any other interesting scenariosthat you might have experienced, heard or know about.
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Old 15th Nov 2012, 07:17
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In this day and age, get onto Stockholm Radio. Then get a phone patch to the head of the HR department.
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Old 15th Nov 2012, 07:48
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What did you answer?
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Old 15th Nov 2012, 08:43
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Before diversion perhaps it may be worth considering what other indications, information would be available for an engine fire, including visual, cabin crew, EGT, FF, etc.. Analysis, is this a time critical event.. NO.. advantages of diversion.. NIL, you may ground A/C and cause commercial problems with pax.. continue to destination and get company maine to sort it out.. just monitor engine as normal... keep it simple...
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Old 15th Nov 2012, 10:45
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...I would advise the Same als Avenger.

Not long after my own upgrade I had the following scenario:

After departure on our way home again we had a decreasing indication of the pressure of the flight crew oxygen bottle. We were already a bit suspicious as the indication on the turnaround was quite a bit lower than when we left home in the morning. No decrease in pressure was observed, all masks were checked, and pressure was above minimum for dispatch on the ground during turnaround, so we went. A decision I regretted, as now -due to the differential pressure- the indication started to decrease and we had an inflight oxy leak on our hands. I never received any guidance on best practices of this or any requirement of flight crew oxy pressure INFLIGHT. But my gut feeling told me that it might be handy to have at least some that stuff during our 2,5hr flight at FL370. So I agreed with my FO that we would divert enroute when the value would reach below a certain value. After that I checked all the masks again and found a light hissing sound on the LHS jumpseat mask. Relief came when I was able to disconnect the hose and stop the leak at 230PSI, only 30 above our minimum agreed value. The hose had a small puncture close to the mask connection.

...for your entertainment.
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Old 15th Nov 2012, 12:21
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Been there too. Brought up the Lower DU for the remainder of the flight. Tech Log entry upon arrival. Rang up Maintrol. Nice lunch in the terminal. Few hour delay and back home.
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Old 15th Nov 2012, 12:24
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Well, a double loop failure is not considered a LAND ASAP situation by Airbus. Other than that, I'm not sure that us mere pilots can come up with a watertight risk analysis for this scenario. What do we know about engine fires other than how to extinguish them? What do we know about other indications of an engine fire? Would EGT rise? I guess it depends. Would oil pressure drop? I guess it depends. Would the engine show any other signs of fire until it's way too late? Who knows!

So other than closely monitoring the engine, shutting it down at the first hint of trouble and firing both bottles I'd continue to destination. That is, if there is any maintenance available at destination! If the instructor is not happy with that answer, then ask him why the MEL does not prescribe any additional procedures.
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Old 15th Nov 2012, 12:34
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What would I do?

1. Fly the plane and confirm the failure
2. Perform the memory items, if any
3. Run the Emergency/Quick Reference Checklist
4. Check the C/B's
5. Check the MEL
6. Make short-term plan on engine monitoring if the checklists don't provide any guidance.
8. Consider - Continuing/Diverting to a maintenance base/Returning.
9. See if I can speak to my Ops. (or send ACARS).
10. Recap with colleague/s
11. Decide next course of action
12. Execute.

What I'll not be doing is shutting down an engine that appears to be working normally.
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Old 15th Nov 2012, 13:26
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No fire/overheat indication systems on one engine means that there is a remote possibility of an aircraft threatening event occurring without adequate warning. Therefore I would assess it as a land at nearest suitable regardless of commercial or logistical concerns.

If when assessing the situation you are lead to believe that the engine is operating normally, then there is no need to unnecessarily add risk by shutting the engine down.

Last edited by Sciolistes; 15th Nov 2012 at 19:47. Reason: Spelling
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Old 15th Nov 2012, 13:45
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Wouldn't the second loop fault (with the first already inop) in fact give you a fire warning?
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Old 15th Nov 2012, 13:46
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How about discuss with operations....If going to a base with maintenance, then continue. If concerned, have an FA watch the visible portion of the engine in case that 1 in a million chance of a fire happens. The good news...no false fire warnings.
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Old 15th Nov 2012, 19:13
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A thought or two, if I may -

(a) intentional launch with a U/S per MEL means that the conditions pertaining to the MEL address a presumed consequent failure ie it's a quasi-"normal" operation. This is one of the reasons that such schedules require multidisciplinary input for the decision process ... the line item sets out to maintain something approximating the original Design Standards requirements ... if the decision is set up by a single discipline, the risk is that matters required to be considered but outside that discipline may be missed.

(b) in-flight U/S is the realm of QRH actions and effecting a safe recovery in the particular set of circumstances. One is well counselled to consider the MEL words as a useful input to the decision process but the intentional launch considerations are not relevant.
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Old 16th Nov 2012, 00:42
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O.K......so what would you do?
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Old 16th Nov 2012, 04:28
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Had this happen to me (Flight mech) half way into a 5 hour flight over water and into a vast green remote area. We turned back to base because it was logical, PIC did not concider a diversion.
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Old 16th Nov 2012, 04:49
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Risk analysis is

Historical tisk of type (includes other manufacturers as well) for diversions, including IFSD, compared to risk of fire at similar flight conditions. Assume significant outcome for either not including fatalities (yes I know there can be a good deal of argument here).

I would say that the diversion risk of significant outcome is about 10000 times more likely on a per flight basis
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Old 21st Nov 2012, 01:25
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Dedicate a cabin crew to monitor the engine through the window and check in with her from time to time in addition to what has been mentioned before.
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Old 21st Nov 2012, 06:34
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Wouldn't the second loop fault (with the first already inop) in fact give you a fire warning?
Modern engine fire detection systems are capable of determining the difference between a fault and a fire by the rate at which the resistance/capacitance in the loops changes.

Regarding engine parameters... Unless we're talking about a turbine overheat detection system, most fire loops will only really tell you what's happening on the outside of the engine (in the cowls). You may have have a raging fire in the cowls long before there are any signs of engine parameter changes.
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Old 21st Nov 2012, 08:02
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Looking at my MEL, there are 3 different detection loops (engine, turbine and nacelle) per engine so presumably only one element of this has failed. In addition to bringing up all of the engine indications (and maybe the occasional visual check from the cabin) I'd be tempted to continue with this mitigation in place (and knowing that I still had two detection systems operating and engine instruments to monitor). We could also discuss in what situations we would fire a bottle i.e. if there was abnormal operation and fire may be possible, fire it (and the other!).

Would then follow-up with a call to the company to see if their take was the same as mine/ours - if not, review my thought process and/or do as the company wishes (in the case of a turnback or diversion) - it's their jet. Route would factor in to the decision too - i.e. over Europe or the Pacific, etc.

Was a study done by the manufacturers suggesting that engine fires pretty much should be self-contained i.e. it's more likely to burn off the pylon than affect the wing?

I'm an FO but like to think about these scenarios...

Last edited by bucket_and_spade; 21st Nov 2012 at 08:05.
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Old 21st Nov 2012, 09:54
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Looking at my MEL, there are 3 different detection loops
Look again. Unless you fly an unusual type, there are probably two loops that have 3 sensing elements (nacelle, turbine and core). So if one loop is MEL and the other goes during the flight, you have no fire sensing capability left. Apologies if your aircraft truly has three independent loop/detectors!

Wouldn't the second loop fault (with the first already inop) in fact give you a fire warning?
On the A320 series the fire warning is inhibited if both loops fail within more than 5 seconds of each other.

P
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Old 21st Nov 2012, 10:11
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during training give them an the answer they want to hear.

in everyday business of course just continue the flight. when you have the rare event of a dual loop failure inflight followed by the very rare event of an undetected engine fire during exactly this leg then lord decided it should happen this way .

correct me, but i think there is in aviation history not one event logged where first both loops decided to quit inflight and then independent of that exactly this engine on exactly this flight suddenly catched fire without notice to the crew.

cheers
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