Display Unit failure during rotation

[Kevingee21]

Hello everyone,

I have a question about a scenario that was recently applied by my fleet for a recurrent test (777) but I think applies to most fleets.

The scenario is during takeoff after 80kts but before V1, the FO side PFD and ND both fail.

My question is do you reject takeoff or not?

According to 777 QRH Maneuver Section on RTO: If below 80kts would probably reject due to this falling under the category of “system failure(s)”

But above 80kts this failure technically doesn’t fall under any RTO criteria except for “airplane is unsafe to fly”

So I guess depends if you think this failure constitutes “unsafe”?

Also suppose I did takeoff with this failure, would I also be legal to continue to my destination (although not encouraged)?

The requirements for 2 PFD and 2 NDs are supposedly for planning stage (required equipment at dispatch).

Any insight or discussions about this is much appreciated thanks!

KG21

[Capt Pit Bull]

GO.

GO!!

Remember, any time something happens in the high speed RTO regime, you don’t have time to diagnose. With the exception of the items listed in your briefing to STOP, most other malfunctions are far more likely to compromise your STOP capability than your GO capability.

I’m not familiar with the 777 however on most types, the simultaneous loss off two screens is not going to be a coincidence. Odds are the screens are fine, but you’ve lost the associated SG or both have no power, which means a bus failure.

but you still have 2 sets of instruments and two engines, so it is perfectly safe to take off.

Once safely airborne, figure out root cause (even money says you’ll find other stuff is unpowered off the number 2 busses, or the SGU is screwed. Run the appropriate NNCs and then TDODAR (or whatever your company decision making tool is). The continue or return decision is going to be situational.

[ScepticalOptomist]

In the high speed regime I would not expect you to stop for partial loss of displays.

Perfectly safe to takeoff.

[blue up]

Wasn't there a Boeing notice in the 744 handbook for a situation where ALL the DUs could fail at exactly the same time due to EIU issues, subsequently fixed by a change in EIU spec? Fixed temporarily by recycling EIU CBs x 3?

[mustafagander]

Definitely GO.
I never operated B777 but on the closely related B744, only reject after 80Kts for the "big 4"
The big 4 -
Eng Fail
Eng Fire
Predictive Windshear
Capt believes the the aircraft can't fly
Should this failure mode - no PFD or ND F/O side - occur, you still have both Capt displays, lwr EICAS screen avbl as ND and ISFD for attitude etc.
Once in the air with safe flight path assured, then run appropriate checklists and decide your next move.

[V_2]

Another subtle consideration not touched on yet, is without their PFD, if the affected pilot is the PM, how are the v1 and rotate calls going to be conducted. The pilot flying will largely looking outside and likely be unaware of the failure affecting the other side and waiting for the usual calls. How does the PM communicate clearly the failure and the requirement for the PF to call/monitor the speeds for themselves. Or can the PM clearly see the other screen on a 777. Startle factor could also of course come into play. Sure sounds straight forward enough here on the ground to communicate the problem, but going down the runway at speed not so easy.

if the affected pilot is PF and it happens just before or during rotation, chances are neither pilot is going to notice 2 screens have failed until already airborne and climbing away. The PF at some point is going to have to hand over control. The urgency of this to happen I imagine depends on most likely the cloud base or visibility.

below 80kts, without the second screen how are you going to cross check the airspeed indications, so stopping should occur either way in that scenario.

[blue up]

Standby instruments, or ISFD, are the fallback but are only of use if you can remember, or have written down, the relevant speeds. Sad day when the Accountant removed the little paper bug cards from the Inventory.

Anyone here every actually had to fly on Stby instruments for real? Just curious. Only ever lost all 6 DUs in the Sim, twice.

KG21. What was your company opinion of that scenario?

[hans brinker]

Our company has an airspeed check at 100kts (A320), if it was before that I would still abort. The scenario doesn't specify who is the pilot flying but the way it is phrased I assume LP is PF. How is the PM supposed to call V1/Vr with no screens? And if the RP was PF, it is probably worse, how is he supposed to fly without instruments ("your controls, my screens are dead" during rotation would definitely cause a distraction...)? A consideration I have with electrical issues like this is that they sometimes grow worse. I know we are all trained to be go oriented in the high speed regime, but I am not sure if this is always simple GO call even though I would elect to continue on a "short" runway.

[PilotLZ]

If you reject for any failure other than the ones listed as mandating a RTO above 80, you will have done the wrong thing. That's it at a first glance. However, there's a catch. What failures make the aircraft "unsafe or unable to fly", as the last point on the list suggests? I'm not aware of any exhaustive list of those. Hence, it's ultimately down to PIC judgement.

[common toad]

Anyone here every actually had to fly on Stby instruments for real?

Yes thank you. I’m not alone in this as many others flying C560XL, Citation X, Dornier 328 have experienced the cascade failure of early low mod state Collins screens. Flying an approach to minima using a SFD such as a Meggitt should be expected of a pilot.

All this talk from magenta-line generation about lack of speed info; do you not know the expected attitudes to aim for? And as for this ‘startle factor’ and ‘no one will notice until airborne’, or how to communicate a screen failure … Are you not trained to always expect the unexpected, monitoring pilot to monitor, and how to communicate a failure?

What has become of the professional pilot and basic airmanship?

[Roj approved]

A very interesting question, here is my take.

As stated earlier, up to 100kts on the A320 is considered "low speed" for a RTO. (It was 80kts from memory on the 787)

On take off, I attempt to quickly scan left to right across the cockpit as we approach the "100kt" call, this takes in My PFD/ND, ISIS, EWD, RH PFD/ND. My theory is I will be aware of any issues with Airspeed discrepancies, failures etc prior to the "High Speed Regime" starting. (this is made more difficult in high crosswind, 30m Rwy or LVP conditions)

Hopefully if I was faced with this failure, I would have enough SA to either STOP or GO in a timely fashion regardless of whether I was PF or PM.

If the F/O is PF, the startle factor and the ability to get a clear message out will be the hardest part.

But that's what we get paid the big bucks for.

[stilton]

Another subtle consideration not touched on yet, is without their PFD, if the affected pilot is the PM, how are the v1 and rotate calls going to be conducted. The pilot flying will largely looking outside and likely be unaware of the failure affecting the other side and waiting for the usual calls. How does the PM communicate clearly the failure and the requirement for the PF to call/monitor the speeds for themselves. Or can the PM clearly see the other screen on a 777. Startle factor could also of course come into play. Sure sounds straight forward enough here on the ground to communicate the problem, but going down the runway at speed not so easy.

if the affected pilot is PF and it happens just before or during rotation, chances are neither pilot is going to notice 2 screens have failed until already airborne and climbing away. The PF at some point is going to have to hand over control. The urgency of this to happen I imagine depends on most likely the cloud base or visibility.

below 80kts, without the second screen how are you going to cross check the airspeed indications, so stopping should occur either way in that scenario.


Keep going



Doesn’t the 777 automatically call out V1 ? not a big deal even if it doesn’t the Pilot whose displays are operating can glance down and determine if VR has been reached

[FlightDetent]

320 trained. Go. Our cut-off is 100 kt, however.

No contest, no justification, no need to stop. As much as I dislike the ad-extremis emphasis on not attempting to stop, more so when 100 kts are achieved still inside the THR-side touch-down markings.

How did we get to the point where stopping safely is a sin would be a different discussion.

EDIT: Hope it is not wrong to assume the PIC eye-focus for the high-speed part is 50% engine, 25% ASI, 25% outside

[vilas]

Our company has an airspeed check at 100kts (A320), if it was before that I would still abort. The scenario doesn't specify who is the pilot flying but the way it is phrased I assume LP is PF. How is the PM supposed to call V1/Vr with no screens? And if the RP was PF, it is probably worse, how is he supposed to fly without instruments ("your controls, my screens are dead" during rotation would definitely cause a distraction...)? A consideration I have with electrical issues like this is that they sometimes grow worse. I know we are all trained to be go oriented in the high speed regime, but I am not sure if this is always simple GO call even though I would elect to continue on a "short" runway.
Being go minded is mind set to have as you move closer to V1 but well short of V1 if not sure nothing wrong in stopping. It could get complicated if engine failed near V1.

[Kevingee21]

Standby instruments, or ISFD, are the fallback but are only of use if you can remember, or have written down, the relevant speeds. Sad day when the Accountant removed the little paper bug cards from the Inventory.

Anyone here every actually had to fly on Stby instruments for real? Just curious. Only ever lost all 6 DUs in the Sim, twice.

KG21. What was your company opinion of that scenario?

Thank you all for the replies!

Our scenario was FO is PF and both of his DU’s failed above 80kts but below V1.

Some IP’s I’ve heard were more oriented toward stopping even close to V1 so I guess that’s what confused me.

Like you guys said, nothing is cut and dry, but the basic premise of consider to GO when closer to V1 I think is a good start.

[Fursty Ferret]

Surely if PM loses their screens they'll just look across and call V1 and rotate off PF's? Or am I missing something here?

[FlightDetent]

Surely if the F/O does not call V1+r ...

[Jwscud]

My employer gave us a fascinating brief and training on takeofff decision making on the A320. The example was EEC in the high speed regime on the 320 which obviously leaves only CAPT PFD/ND and the upper DU.

On a short runway rejecting for this (the warning for which is which is inhibited above 100kts) leads to a runway overrun due to the loss of a large number of stopping devices. The emphasis was Airbus have done the thinking for you in the ECAM and inhibit design, and to trust it. Certainly I (current Airbus captain) wouldn’t consider loss of one side’s displays as “malfunctions or conditions that give unambiguous indications the aircraft will not fly safely” - in this case I think the Airbus FCTM wording makes the point about what you should be considering much better than the Boeing.

[Check Airman]

Surely if PM loses their screens they'll just look across and call V1 and rotate off PF's? Or am I missing something here?

I thought it would have been an obvious solution. Not sure how the 777 is set up with the yoke in terms of visibility, but the visibility on the Airbii is quite sufficient for either pilot to read the offside PFD.

[BraceBrace]

It’s an indication functionality, not a unsafe aircraft. Look on the MCP, there’s your V2. Use it as a rotation speed, or use runway lights. It will fly safely, don’t worry. Why would you want to reject a perfectly safe aircraft with double indications available (stand-by and PF side)?

Btw, I believe on the 777 the PFD display will automativally transfer to another display.

[Good Business Sense]

Wasn't there a Boeing notice in the 744 handbook for a situation where ALL the DUs could fail at exactly the same time due to EIU issues, subsequently fixed by a change in EIU spec? Fixed temporarily by recycling EIU CBs x 3?

Hi, that happened to me when I was an FO on the 744 back in1990 - happened on rotate into a very low cloud base. I was flying - those the little standby instruments are more orientated for the Captain. To say it was stressful was an understatement - pitched to 15 up and used TOGA ...... mentally DRd the SID until above MSA. Took us a long time to deal with this situation.

The other big memory was the noise from all the warnings (the ones you can't cancel), myself and the Captain couldn't really communicate - this is an issue, same as would have been experienced on the AF over the south Atlantic, which is never raised. With the noise you cannot communicate nor think properly.

To the original poster - just before VR all the screens started flashing before they all were lost ...... so stopping "might" be a good idea in your scenario.

Best

[Good Business Sense]

If one cannot stop ANY large aircraft at 100 kts, then the rwy was most likely too short to start with.
rules are one thing in a simulator. Answers in an interview are one thing. Common sense is something else in the real world.
depends upon the situation, the speed, the environment, etc. If lots of rwy, and or stopway, dry, why not stop? If short, wet, contaminated, then go. “PIC” must still have some real meaning left in it.
is the screen failure really the ONLY failure there was?
a rigid mindset is not always a good thing. The B2 bomber that crashed after TO after a master caution, that cleared itself, implies that each situation must be considered carefully.
look how confused pilots can get with airspeed disagree during a TO. Consider how difficult it can be to fly with an airspeed disagree with all the warnings going off.
each TO is unique in many ways. When we start operating like robots, then the most useful tool is diminished.
this will most likely be deleted by the moderators and if not, I await the expected condemnations.
no one can really answer these difficult questions for you.
you must answer them yourself.

On a very, very light A330 take-off at night/rain (the usual) the FO called 100 kts - I had about 75/80...... I said something like, call the speed again ..... he was totally confused (nobody trains for this) and couldn't respond before we went through VI/Vr - didn't matter as my airspeed hadn't increased much - I rotated to 15 up on the standby and selected TOGA. Biggest problem, due to the time available at that stage is that you don't know what data is correct (you are looking at a display with multiple display warnings that you have never seen before). Trying to ignore the bad data i.e. everything on my PFD, particularly the speed was really difficult. The brain is funny - when you have been looking at something like a PFD for thousands and thousands of hours and it has always been correct it wants to believe what is displayed even when you know it's wrong - somehow you need to removed the erroneous data. Used to be the same with map shifts - back in the day

I think we were through about 3/4,000 feet before the PM/PNF got his brain in gear (not surprised).

In my opinion the Airbus 100 kt call on a light aircraft is not fit for purpose - preferred the Boeing 80kt call.

Found this and the loss of all screens on a 744 at rotate to be, by far, the most difficult emergencies that I ever had to deal with in 40+ years.

Best

[judge.oversteer]

Continue. When safely airborne Engage the Autopilot. As others have said it's an indication problem.
Then select another screen and do checks. Perfectly good aircraft otherwise.
Old B744 Trainer.

[pineteam]

EDIT: Hope it is not wrong to assume the PIC eye-focus for the high-speed part is 50% engine, 25% ASI, 25% outside

From my understanding of the FCOM procedure for take off. the PF (regardless of being PIC or FO) is not supposed to monitor the engines indications during the take off roll. This is done by PM only. That’s why when the PM announces “thrust set” there is no acknowledgement from the PF. I personally when I’m PF will usually have a quick glance at least once at the relevant engines parameters (N1/EPR & EGT) but otherwise it’s outside and inside (PFD only).

[stilton]

I thought it would have been an obvious solution. Not sure how the 777 is set up with the yoke in terms of visibility, but the visibility on the Airbii is quite sufficient for either pilot to read the offside PFD.


This is one case where having a HUD would be very useful

[FlightDetent]

From my understanding of the FCOM procedure for take off. the PF (regardless of being PIC or FO) is not supposed to monitor the engines indications during the take off roll. This is done by PM only. (in a desperate tone) My understanding of the PIC's job is that he needs to know.

The idea of PIC not looking at the engines at all (and SIC if PF even), or PF depending on PM's speed callouts, because it is assumed correct not to scan the instruments, gives me goosebumps.

[pineteam]

I invite you to watch the video on WIN Website: Role of the pilot monitoring during takeoff. You will see that the captain does not even glance once on the EWD.
The role of the PM is critical and shall be taken extremely seriously during takeoff.
I once went off the runway while practicing v1 cut in the sim with 20kt crosswind. Long story short, 100% my fault; I was 1 or 2 seconds heads down too long with the wrong rudder input cost me a runway excursion and a big slap on my ego lol. That’s why now I’m much more focus at looking outside making sure I have the aircraft under control in case of something bad happens. =)

[FlightDetent]

I invite you to watch the video on WIN Website: Role of the pilot monitoring during takeoff. You will see that the captain does not even glance once on the EWD.
Let's wait for a video about instrument scan for PIC (before V1), shall we?

[CVividasku]

Speaking from a 320 F/O perspective.

While I agree with most of what's been said, I'm a bit surprised regarding one missing element.
Why not add a word about the weather ?
Imagine if it's a cat 3 takeoff. You have your alternate at, say 45 mins of flight.
If you takeoff, you can't land at your takeoff airport because it requires 2 PFDs.
You can land at your takeoff alternate (or destination if very short flight), because at least one of them is not cat 3. But during takeoff you don't have any time to analyse and guess if your screen problem will not extend to the other screens, or other systems of the aircraft.
Plus, during LVP, it can be good practise to increase a bit takeoff thrust from the max flex habit of blue sky weather. So you have more margin for stopping.

So if we were, for example, halfway into the high speed phase in cat 3 weather, I would expect the captain to stop the aircraft if he lost his screens, and I would say something to that effect if I lost mine.

Blue sky weather, GO would probably be the decision, but there would be serious discussion about stopping the flight immediately.
What if the screens shut off as a result of a short circuit and impending electrical fire ?