A320 Emer Elec short before v1

[Speedwinner]

Hello friends,

that Scenario is often briefed: a total electrical failure (emer elec) before v1.

in case we abort the takeoff: what can we expect, what are the big Players? is the reverse working?

in case of go? what are the indications left?

Thanks so much!

SW

[juliet]

Need a bloody good reason to stop. And a long runway.

[PEI_3721]

Speedwiner, if you brief this scenario then you really should know the answers to your questions.
By all means ask others for their views, but definitive information from an open forum may not very reliable, or difficult to judge.

You should have access to the relevant technical manuals and operating procedures; ask your captain to explain the briefing, seek advice from instructors, and consider using the simulator.

[juliet]

You’ve read the FCTM and FCOM sections covering this? Do you have the OLB to input some numbers?

The table in the FCOM lays out exactly which systems you will have, and the FCTM talks through the problem as well.

Which part of the manuals is causing the problem?

[mcdhu]

Have a look at the UK AAIB accident report 8//2000 G-OOAB which will give you some insight into stopping from close to V1 at max weight (in the middle of the night).
You brief what exactly you are going to stop for and then you must stick to that.
It would be a great one to run in the sim. The big one would be Antiskid?
Cheers
mcdhu

[pineteam]

You should continue even if it's scary as hell as you will lose all EFIS for few very long seconds. I practiced in the sim last year during my upgrade and that's what I was told.
Since you have no reverser, only alternate braking without antiskid, only 2 spoilers per wing, you will most likely overrun if you decide to abort.

[vilas]

This one is not easy nor that straight forward. ASDR doesn't take into consideration reverse but yes anti skid. New aircraft the brake pressure is automatically controlled at 1000psi. The decision to go is based on the assumption that everything will work as it should in the air. With gear down aircraft will be in direct law. With only ELAC1 and SEC1 should anything happen further it is scary. I won't blame if any one went for reject.

[MD80rookie]

If all screens go blank momentarily just before V1 almost all pilots would abort by reflex, I guess. The briefing item would be "Loss of AC power before V1", right? It takes a few seconds for the systems to come back online after a loss of AC power and during that time frame almost everyone would abort.

I have never, nor have I heard, anyone brief this possible scenario.

[Denti]

I would hope not. If the screens go momentarily blank you don't even know if you're below V1 or above. One can rotate with a look outside or on the ISIS, but just aborting because you're startled is a very dangerous thing.

Actually had that happen at one time in the past, however, that was a simple signal generator failure on my side, not something as serious as emergency elec configuration on the bus.

[Escape Path]

I did it on my last sim. You're in for a shock if you don't have a long enough runway! As stated above, you won't have reversers; if on a later MSN you will have auto regulation of the brake pressure, if not, easy on the brakes! Takes a damn long time to stop and mind you, we did it on a 3800m long runway (although at 8300 ft high).

As pointed also by others, it's quite a shocker (since you normally don't brief for that one, so you don't know what signs to look for). Everything just goes dark, you lose all screens and it even goes a bit quiet (after the gens cut off-line!). A reject will be what most would do, out of pure startle I think. Might not work on a short runway + high speed...

Would this one fit under "unambiguous indications that the aircraft will not fly safely"? As vilas pointed out, the go decision would be made under the assumption that everything will work fine after the longest seconds in aviation history. It should fly safely, but...

[vilas]

Nobody briefs about such multiple failures in takeoff briefing. There are any number of messed up rejects without such complications. More items you add more chances of screwing it up. Despite this briefing some may reject after the startle beyond V1. For such a major failure out of nowhere it is safer to drift of the runway end at slower speed than land up in mechanical backup in the air.

[FlightDetent]

It is a bit like discussing how to drink from a broken glass. No successful outcome possible, and time ... gone, to say the least.

According to AFM and FCOM, it is clearly a STOP decision.

Speedwinner: when you say "Scenario is often briefed" what do you mean by that?

[vilas]

This particular failure scenario is a fancy of some TRE. Simulators don't kill but real life could be a bitch. First near V1 you don't have the time to find out what has happened. It is dangerous to assume the screens will be back. With ELAC2, SEC2 gone all it needs is loss of Blue hydraulic to put you in mechanical backup. RAT malfunction would give you that. Would you prefer to crash during landing in mechanical backup at approach speed or trickle out of the runway end at lower speed after a reject?

[Border Reiver]

I would prefer to have options. Airbourne, even on the stby instruments, with the gear coming up gives options. Off the side or end of the runway gives no options at all.

[PEI_3721]

vilas, you argue logically for balanced risk, but this view, and as with other posters’ views, assumes that the situation is known - understood, clearcut, etc.

Assumptions such as these are a weakness in simulation training - incorrect focus on testing the crew in managing an unusual situation, or even biasing decisions against a ‘go’ mentality above V1. Whereas the real learning value is in recognising unusual situations and relating them to an appropriate course of action, particularly where associated with surprise - sound, vibration, blank screens, ...

Regulators and manufacturers will have both the information and time to judge unique situations and recommend safety procedures. Crews should not be expected to identify and relate the complexity of the situation during take off; stop/go situations need to be a simple binary choice.
In many instances with time critical situations generic failures may be assumed. Failures with clear warnings can be separated - fire bell, but less clear situations are often grouped by collector alerts and action e.g. any high priority caution before V1, then stop. Don’t try to rethink many hours of design and regulation deliberation into the 1-2 sec before V1.

Similar considerations should be applied to forum debates where the design/regulatory details may be unknown.
Is this situation really ‘often’ briefed ?
What is the probability of occurrence, what other aspects might be assumed; why is the question being asked?

[Escape Path]

Not once have I briefed/been briefed on this failure on a line flight. I agree stop/go decisions should be as easily made as possible; TBH we had this failure on the sim which is dark and the engine/ambient noises are a bit muffled so the startle factor by mere absence/diminishment of other clues was greater. I imagine taking off at night would create a greater startle factor than at daytime, but I'm not sure and I don't want to find out either. Losing all screens at once means something really wrong has happened and there's no time to diagnose what else is wrong. Given with little time to decide I'd make a case for a "positive indication the aircraft won't fly safely"; if before V1 you'll possibly go off the end but hopefully you'll be going slow enough... Making a go decision with limited time/information about such a critical and unusual scenario (i.e. You most certainly won't know exactly what's gone wrong) makes me cringe a little bit.

Plus I don't know what's the failure possibility (to deploy/ engage) of something that's virtually never used. I assume it's tested on some check in the life of the aircraft, but...

[StrongWind]

This warning is inhibited from 80Kts until Lift Off...
It's not recommended to reject the take-off as you will lost all reversers/ Spoilers 1 2 and 5 and Normal braking.
In that case you will not have enough runway length to stop safely.

Better to get airbone with you Stanbby Instrument, retract the gear.
You will stay in Alternate Law (Not really hard to fly the aircraft in such configuration).
As soon as the RAT is deployed you will recover PDF1 ND1 and Upper ECAM, enough to manage the flight and come back on a long runway to stop the plane.

[vilas]

If the rat doesn't deploy you go in mechanical backup. Have you done approach and landing in mechanical backup?

[Goldenrivett]

vilas
If the rat doesn't deploy you go in mechanical backup.
Why?

According to QRH, you don't loose all 5 fly-by-wire computers or both elevators or total loss of ailerons and spoilers if the RAT doesn't deploy. You'll have "BAT Only" power available (until it runs flat).

[Denti]

If the rat doesn't deploy you go in mechanical backup. Have you done approach and landing in mechanical backup?

That is a difficult way of arguing in itself, because it includes the premise that any other redundancy might not work either. So why not abort a takeoff after a V1 cut? After all, the other engine might stop working soon after as well and then you are even worse off.

Yes, the RAT isn't used every flight, unlike both engines. And yes, that does not instill confidence that it works. However, as a last ditch redundancy barrier we have to believe airbus that it does not fail. Same as all other redundancy barriers we do have on that plane.

And to answer your question, yes, mechanical backup was not part of the official syllabus in my typerating, but we trained it nevertheless in the simulator. As far as i know it hasn't happened in real life yet.

[EcamSurprise]

If they wanted you to stop for it.. why would it be inhibited?

[vilas]

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.

[Goldenrivett]

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?

[Denti]

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.

[PEI_3721]

Denti, :ok:
Now, how might we communicate ‘common sense’, tacit knowledge, during training ?
First identify and check assumptions ?
Good system knowledge ?
Apply knowledge ?

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

[Escape Path]

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

[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?

[dream747]

From my FCOM, Emer elec is inhibited in phase 4, that is above 80 knots to liftoff.

[Denti]

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.

[*Lancer*]

After 80kts, it’s 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 you’ve covered to get to V1 to have a rough idea of what ASDR you’d need. It’s a lot.

[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 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.

[FlightDetent]

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.

[*Lancer*]

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.

[Escape Path]

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

[PPRuNeUser0190]

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

[vilas]

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.

[FlightDetent]

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.