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A320:Unreliable Airspeed

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A320:Unreliable Airspeed

Old 9th Jan 2021, 15:25
  #21 (permalink)  
 
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Let's get to present case. Let's say both capt and copilot Pitot inlets blocked(not total dual Pitot block which the article forbids) Even this will give wrong airspeed both side. How does handing over help? Instead after takeoff you just fly 15 pitch is it some complicated procedure? Then after checking the third i.e. ISIS for confirmation If PF uses transfer isn't it safer? How can you transfer without ensuring the PM has speed. What safety first says is not to use Dual total Pitot blockage that includes drain holes.
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Old 9th Jan 2021, 16:06
  #22 (permalink)  
 
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Don’t over think it. At low altitude follow the memory items if you can’t figure out what IAS Is correct or not sure what is the pitch and thrust setting required at that instance to keep a safe flight path and in the cruise, rule of thumb: Pitch 2 degrees up and 80 % N1 or whatever cruise power was set if you have thrust locked and you will be fine.
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Old 9th Jan 2021, 16:26
  #23 (permalink)  
 
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Thanks vilas, pineteam....overthinking tends to be an issue for me for sure! and what we did was at low altitude, and was the memory items for unreliable airspeed (albeit badly executed by me!) due to doubt as to PFD (CM2) reliability. And then level-off and verify (using eQRH) as the plan to confirm the serviceability/reliability of my PFD airspeed (i.e. if pitch and power matches approx., then reasonably assured that it's working and reliable in absence of anything else). Perhaps I need to memorise some pitch/power settings as a back-up? although I'm not a fan of such things because of the possibility of mis-remembering and inducing errors where there were none ;-).
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Old 10th Jan 2021, 05:24
  #24 (permalink)  
 
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I would not recommend to try memorize them. Make sure you know your memory items by heart. The one in cruise 2 degrees up and 80% n1 is important to know. You don’t want to go 5 degrees up and climb power at high altitude... At lower altitude in clean configuration pitch 2 degrees up and 60% N1 you will be safe too. With experience if you pay attention to the pitch and thrust setting during flights you will have an idea. Sometimes I play a game in my head and try to guess what will be the pitch and N1% when I level off. Saying that, all you have to do really is to follow the memory items if required or just maintained the same pitch and thrust setting at the time of the failure and ask the PM to give you the pitch and N1 setting. I know by looking at the QRH procedure it looks overwhelming but it’s not that bad really.
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Old 10th Jan 2021, 07:46
  #25 (permalink)  

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Originally Posted by vilas View Post
What first officer has stated is from FCTM. Unrealistic scenario in the simulator is a different aspect. FCTM cannot be ignored.
Exactly my point. Both the blue graphics and the text say to apply the memory items only in case safety of the flightpath is affected. At least that's my interpretation of it.

To apply memory items of UAS when uncertain is a valid and necessary correct step for complex scenarios where the indications make little to no sense. In the realm of what actually might happen that is
- radome destruction
- insect infested/blocked pitots
- protective covers left on
- purposely created unrealistic SIM scenario of another freak type (the real existence of unrealistic scenario)

On other occasions there will be some good indication the crew could work with. Applying TOGA+15 indiscriminately and reactively, without trying to assess the situation first and trying to make sense of it, is actually plain wrong. And the book confirms that in writing.

Problem with TOGA + 15 is the performance, ATC liaison and altitude control. Not to sidetrack too much, we all know that dual engine GA are an identified weak spot of pilot performance worldwide - the reasons and effects are of the same ilk here, in my opinion. Also, simulator experience shows that. Rubbing more salt, us busting 600 m without a clearance, UAS or not, would had put my employer in a bad position and myself plus the crew grounded with no pay and possibly demoted.

Most of the times it is possible to tackle a problem from more angles then just one. For the record, I am speaking of correct angles, not pilot creativity. For obvious reasons yet the FCTM provides only one solution, which is an optimized compromise and covers the widest variance of the underlying problems and most conservative way of handling them. The FCTM has been fine tuned to near perfection over the years and the magnificent effort Airbus puts to the multitude pilot and operator conferences. As a matter of fact, the solutions provided within are to be considered obligatory unless clearly not applicable. That is not the case of ADR1 fault resulting from a bird strike destruction of the onside sensors. One could argue that it is the baseline air data trouble and if the FCTM was to cover only one particular case this would be it.

Slower is better than quick, coordinated with colleague is better than impulsive. Given the description provided, the OP is correct to seek improving his performance the next time.

First.officer Realistic and slightly under-excited, ever doubting, view of one's own performance is one of the finest qualities in a pilot. You may well be in the correct job, although not the optimum chair yet.

Imagine if this was a real estate agents forum, we would be discussing how best to conceal problems on a property ery and modern trends to hype the customer.

Piloting gives you the chance to be proud and rewarded for doing the correct and truthful thing. That is not at all commonplace!


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Old 10th Jan 2021, 08:04
  #26 (permalink)  
 
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On other occasions there will be some good indication the crew could work with. Applying TOGA+15 indiscriminately and reactively, without trying to assess the situation first and trying to make sense of it, is actually plain wrong. And the book confirms that in writing. Problem with TOGA + 15 is the performance, ATC liaison and altitude control. Not to sidetrack too much, we all know that dual engine GA are an identified weak spot of pilot performance worldwide - the reasons and effects are of the same ilk here, in my opinion. Also, simulator experience shows that
When close to ground when your FD could be wrong is not a situation that affects flight path? UAS is May Day. We are not going round where there's large flight path and thrust change, we are airborne and climbing may be with TOGA, we just want to ensure that without the possible misguidense by FD. Keeping FLEX is not a problem but following FD could be dangerous.
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Old 10th Jan 2021, 09:33
  #27 (permalink)  

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Neither of us explicitly said so yet, it occurs to me now that we both are indeed pushing for the same thing: Steady pitch! Without it, the safe flight path will be compromised.

You say TOGA + 15 always assures a safe pitch.
I say a safe pitch is already there, just start off with not changing it before jumping forward unnecessarily.

Both correct in its own right and complementing one another.

Following the flight-directors somewhere is definitely lethally undesirable and while they'd be removed for many cases anyway, for a good number of others they are not. When I said do nothing it for sure is not following wayward FDs. How different the outcome of AF447 could have been.

Yes, realizing the FD's are misguiding is one of the greatest challenges, naming one reason it requires skill and attention to other instruments engraved in the retinas and the whole industry seem to conclude we can go on without having that. Well, until the day...

That is when TOGA+15 becomes the safeguard of the first choice, I cannot really dispute that. It's great to see people who strive to do better.

Thanks for the inputs and reflections shared, again.
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Old 10th Jan 2021, 10:12
  #28 (permalink)  
 
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I think moving forward, I can see that what I/We did on the day in question....was destabilising and unnecessary in the circumstances of what was simulated, albeit I was trying for (what I considered) would be the safest outcome overall. I certainly made the situation worse. I find that the more I read (learn?), the more questions I have in relation to what's written, and what perhaps is not written - this I appreciate is not possible to cover all scenarios and options that may occur, and is where airmanship/ANC and CRM come in to play, and what makes the outcome the best that it can be. Thanks again for all the comments, it's good to read through and learn and see differing viewpoints.
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Old 11th Jan 2021, 16:51
  #29 (permalink)  
 
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UAS is not a time critical item. Pilots need to assess what the aircraft is doing. A modern cockpit gives so many ways to do that. You have VSI’s, GPS speed, aircraft attitude, thrust, back up pitot static indications and even ground speed from controllers. Every professional pilot should know the basic attitude/power for the normal flight regimes. You can’t go very far wrong if power and attitude are correct for a given phase of flight. My experience losing airspeed on both sides on a 767 during approach was simple. Maintain 2 degrees nose up and adjust power to maintain the proper VSI and glide slope indications while cross checking GS. It was I admit easier than some situations because we were fully configures and stable at the time. Had we gone around it would have become a much more complicated problem. I recently lost airspeed in a high performance light aircraft without a lot of fancy backups. Managed to center punch what must have been a very large bug and block the pitot completely. Attitude plus power equals performance! Held my normal climb attitude/power until 3000’. Leveled off and drug out my IPad to get a GPS backup for speed and returned to land.
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Old 13th Jan 2021, 18:38
  #30 (permalink)  
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Thanks everyone for the information.
One more doubt.

In normal operations the airspeed indication on ISIS is supplied by ADR 3?In case of unreliable airspeed ,the cross check with ADR 3 speed is done by directly reading it from ISIS or I have use the switching panel to see ADR3 airspeed on either PFDs?
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Old 13th Jan 2021, 21:54
  #31 (permalink)  

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FCOM-DSC-34-NAV-10-10 "C"
Navigation > ADIRS > Descritpion > Probes Schematic

Again, the NOTE has what you're looking for.
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Old 14th Jan 2021, 13:19
  #32 (permalink)  
 
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Originally Posted by Learningtofly85 View Post
Thanks everyone for the information.
One more doubt.

In normal operations the airspeed indication on ISIS is supplied by ADR 3?In case of unreliable airspeed ,the cross check with ADR 3 speed is done by directly reading it from ISIS or I have use the switching panel to see ADR3 airspeed on either PFDs?
ISIS gets standby Pitot/staic pressure direct without going through ADM. ADR 3 gets also gets through same source but through ADM. You can check even by switching also directly from ISIS.
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Old 16th Jan 2021, 16:06
  #33 (permalink)  
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Thumbs up

Originally Posted by vilas View Post
ISIS gets standby Pitot/staic pressure direct without going through ADM. ADR 3 gets also gets through same source but through ADM. You can check even by switching also directly from ISIS.
👍 thank you
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