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A320 Emer Elec short before v1

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A320 Emer Elec short before v1

Old 19th Mar 2018, 14:56
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If they wanted you to stop for it.. why would it be inhibited?
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Old 19th Mar 2018, 15:37
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Denti, Goldenrivett
The aircraft manufacturer hasn't said a word about reject for ELEC EMER before V1. I dealt with 13 airlines SOPs from India to Japan none have it. Why is that? Firstly in this idea it is assumed that a pilot can figure out in a second that it is ELEC EMER. I am not sure of that. Second the only consideration is ASDA which may not be a factor on many runways. Third it is assumed that suddenly two AC buses can pack up but RAT will work. I am sure the person who has brought this idea doesn't know that if RAT doesn't work you land up in mechanical back up. In ELEC EMER you loose ELAC2 and SEC2. If you now loose blue you go in MBU. If you have done MBU in SIM how do you think you get in that? Next time try it. In airbus never develop your procedures without consulting the manufacturer. Trying to find a cure for something that has never happened and that too may turn out deadlier than the disease.
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Old 19th Mar 2018, 15:48
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vilas,
I am sure the person who has brought this idea doesn't know that if RAT doesn't work you land up in mechanical back up. In ELEC EMER you loose ELAC2 and SEC2. If you now loose blue you go in MBU.
According to my QRH, ELEC EMER CONFIG Sys Remaining (Cont'd):
Applicable to ALL:
FLT CTL... with EMER GEN you have ELAC 1 only.
BAT only in Flight... you have ELAC No1 & No 2.

So why do you think we end up in MBU. What am I missing?
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Old 19th Mar 2018, 18:23
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Originally Posted by vilas
Denti, Goldenrivett
The aircraft manufacturer hasn't said a word about reject for ELEC EMER before V1.
Actually, he has. Very clearly. It is a fault that is inhibited from 80kts until Liftoff. For a very good reason i would think. Therefore it is not a reason for a takeoff abort according to the FCOM.
I dealt with 13 airlines SOPs from India to Japan none have it. Why is that? Firstly in this idea it is assumed that a pilot can figure out in a second that it is ELEC EMER. I am not sure of that. Second the only consideration is ASDA which may not be a factor on many runways.
Same for Engine failures after V1 methings, still we take it into the air. However, on the other hand it might be limiting. We're just coming out of winter season over here in europe and we had our fair share of low braking action runways to take into account, and airbusses routinely operate out of airports with runways of well less than 2000m which are usually very much limited even under normal conditions.

The argument about the non limiting runway is actually a huge red herring and usually used by those trying to defend their own SOPs that are not OEM sanctioned.

Third it is assumed that suddenly two AC buses can pack up but RAT will work. I am sure the person who has brought this idea doesn't know that if RAT doesn't work you land up in mechanical back up. In ELEC EMER you loose ELAC2 and SEC2. If you now loose blue you go in MBU. If you have done MBU in SIM how do you think you get in that? Next time try it. In airbus never develop your procedures without consulting the manufacturer. Trying to find a cure for something that has never happened and that too may turn out deadlier than the disease.
Again you assume that a last barrier redundancy doesn't work. Which is not the premise that either airbus uses nor the certifying authority. And neither can we. That road is a very dangerous one to go down, as it opens a huge can of worms. Following that line of arguing leads straight to non-OEM home cooked SOPs that are most probably much more dangerous than the problem they try to solve.

The procedure for emergency elec configuration does not even assume that the RAT cannot work, which is only possible if that is a 10^-8 case. And even if that would be the case, emergency elec config without RAT is still in alternate law in pitch, direct law in roll and mechanical in yaw. At least according to the FCOM i have in front of me. Which is very much flyable. At least in the 20 minutes until the battery runs out, which is quite enough to get it onto the ground at the beginning of a runway instead of trying of stopping in the last 500m.
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Old 19th Mar 2018, 18:49
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Denti,
Now, how might we communicate ‘common sense’, tacit knowledge, during training ?
First identify and check assumptions ?
Good system knowledge ?
Apply knowledge ?

vilas,
‘Don't try to out think critical situations’, but how might we teach or control the required mode of thinking ?

Last edited by PEI_3721; 19th Mar 2018 at 22:06. Reason: Typo
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Old 19th Mar 2018, 23:33
  #26 (permalink)  
 
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Is there any known case of a RAT failing to deploy?

Making a go decision on this case is very difficult. As others said, some runways will be limiting and some won't. The stop/go decision should be as easy as possible particularly for failures that won't happen too often (as they won't be briefed). For the case of a limiting runway, the chance of a major cock up is too big, you'll most likely plow through the airport fence at XX knots.

I guess GO and praying the RAT deploys is, statistically at least, the safer choice
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Old 20th Mar 2018, 02:24
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Denti & Golden
I stand to be corrected. Although ELAC1+ELAC2+BLUE puts the aircraft in MBU, ELAC2 is only lost with EMER GEN RUNNING. Both ELACS are made available for batteries only case (smart aircraft that it is) So my premise was incorrect. Sorry! Now coming to inhibition of failures on take off are you sure that ELEC EMER is inhibited? it is a red warning. Because for continuation of takeoff it says any red warning or amber ECAM caution of ENGINE or FLT CTL SYSTEM which means some warnings are not inhibited. Does any one know what are those?
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Old 20th Mar 2018, 03:14
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From my FCOM, Emer elec is inhibited in phase 4, that is above 80 knots to liftoff.
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Old 20th Mar 2018, 04:56
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Originally Posted by vilas
Denti & Golden
I stand to be corrected. Although ELAC1+ELAC2+BLUE puts the aircraft in MBU, ELAC2 is only lost with EMER GEN RUNNING. Both ELACS are made available for batteries only case (smart aircraft that it is) So my premise was incorrect. Sorry! Now coming to inhibition of failures on take off are you sure that ELEC EMER is inhibited? it is a red warning. Because for continuation of takeoff it says any red warning or amber ECAM caution of ENGINE or FLT CTL SYSTEM which means some warnings are not inhibited. Does any one know what are those?
As dream747 says, it is inhibited in phase 4 and 8.

Yes, the FCOM says stop for all red warnings and 5 specific amber ones (F/CTL Sidestick Fault, ENG Fail, ENG Reverser Fault, ENG Reverse Unlocked, ENG Thrust Lever Fault). An up to date list of all possible red warnings would be nice, however i haven't found that yet. But one could always go through all ECAM warnings/procedures to check out which are not inhibited during phase 3/4. However, as systems evolve that list might change over time.
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Old 20th Mar 2018, 13:40
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After 80kts, its not one of the specified conditions requiring RTO. The warning is inhibited because you have very, very seriously degraded stopping capability and the aircraft is able to fly. Similarly for 2x HYD system failures.

Look up the unfactored landing distance for EMER ELEC CONFIG, then add whatever distance youve covered to get to V1 to have a rough idea of what ASDR youd need. Its a lot.

Last edited by *Lancer*; 20th Mar 2018 at 13:54.
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Old 20th Mar 2018, 15:52
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Better to get airbone with you Stanbby Instrument, retract the gear.

Not specifically Airbus, and much of the technical reasons to not RTO have been mentioned, but I wonder how many pilots, and especially todays MPL quick command cadets have ever looked at the SBY instruments.
In my Boeing days, B732, B757/767 it was a command upgrade item to fly an ILS on the tiny SBY display. Scanning that and the RMI was challenging, but very workable. Then, on modern jets e.g. NG's, a customer option was full PFD on SBY. That is if the screens still work. If the SBY displays are there, then a competent captain should be able to fly an ILS or cloud break on them; but I wonder how many today can, or have ever tried.

Slight digress, I apologise.
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Old 20th Mar 2018, 20:01
  #32 (permalink)  

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Originally Posted by Denti
But one could always go through all ECAM warnings/procedures to check out which are not inhibited during phase 3/4. However, as systems evolve that list might change over time.
True, to rub more salt we'd need to study the T.O.INHIB filter as well.
----

The OEM guidelines are written in quite a deep detail. Whoever needs (*) the answer on this will find it printed clearly.

(*) But do we? I actually think not. Too austere.
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Old 20th Mar 2018, 23:43
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Rat 5,

CPT primary instruments should recover with EMER ELEC. Standby PFD (ISIS) will work on batteries only.

TOGA 10 deg will always get you off the ground and flying.
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Old 21st Mar 2018, 02:29
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Originally Posted by RAT 5
If the SBY displays are there, then a competent captain should be able to fly an ILS or cloud break on them; but I wonder how many today can, or have ever tried.
I'm not a captain, however, we've done FCU 1+2 fault on the sim, which leads to flying with the Stby/ISIS due to loss of baro ref (it goes to std). It's a bit "uncomfortable" but shouldn't lead to any serious problem if done properly, I think.

Plus, if losing all instruments (which in theory shouldn't be the case), I guess one could use the Unreliable Airspeed tables to sort it out, though it isn't a particularly nice way to fly. I reckon it's more of a flight controls degradation vs stopping capability problem than a instrumentation problem.

I think the warning being inhibited above 80kts answers our question, as dire as some of us think the answer is
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Old 21st Mar 2018, 09:58
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Originally Posted by RAT 5
Better to get airbone with you Stanbby Instrument, retract the gear.

Not specifically Airbus, and much of the technical reasons to not RTO have been mentioned, but I wonder how many pilots, and especially todays MPL quick command cadets have ever looked at the SBY instruments.
In our typerating syllabus, loss of all AC power prior v1 is an excercice. When we used to have b737 CL this meant losing all flight instruments till airborne.

Tricky failure due to startle effect, especially night. Our company's advice was to rotate using visual cues (last 600m).

About the multiple failure cases. Don't be too paranoia. What if the TFS ATIS says "WS reported". You take off and get an engine failure :-p
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Old 21st Mar 2018, 11:37
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Escape Path
we've done FCU 1+2 fault on the sim, which leads to flying with the Stby/ISIS due to loss of baro ref (it goes to std).
That is not the way to handle the problem. You have PFD with altimeter stuck on standard. Set ISIS altimeter to QNH. Either note the difference and fly normally with PFD or only use ISIS altitude. Don't throw the baby with bath water.
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Old 21st Mar 2018, 21:11
  #37 (permalink)  

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Originally Posted by rvblyky7
When we used to have b737 CL this meant losing all flight instruments till airborne.
Exactly why I think the question had been posted. Training protocols carried over from another aircraft type.

B737cl is my ex too. Loss of all elec below V1 was a training item just like a tyre burst. Methodically similar: perfectly flyable a/c without any relevant degradation, as opposed to dubious braking. The choice is clear, so we got trained to take it.

On an ECAM equipped A/C however, the colour coding combined with T/O inhibit is sufficient to guide the pilot along the lines the designers and certifiers explored for them.

----

Let's not forget the ELEC system of the 320 is ETOPs compliant, so EMERG ELEC is a multiple, non-related (albeit on the same system) failure combination.
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