A320:Unreliable Airspeed

[vilas]

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.

[pineteam]

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.

[First.officer]

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 ;-).

[pineteam]

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.

[FlightDetent]

Originally Posted by vilas

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.
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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!

[vilas]

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.

[FlightDetent]

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.

[First.officer]

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.

[Sailvi767]

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.

[Learningtofly85]

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?

[FlightDetent]

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

Again, the NOTE has what you're looking for.

[vilas]

Originally Posted by Learningtofly85

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.

[Learningtofly85]

Originally Posted by vilas

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

[Lantirn]

Have a question and since the subject is relevant, will post it here to not open new thread.

When in takeoff, in a speed discrepancy between PFD1 and PFD2 you apply memo items. When in cruise you dont have to, since the safety of the flight is not impacted. 2,5 and 78 and off you go for the 320.

What is not clear to me is how you handle that when climbing and passing lets say 10.000

Do you still apply memos and then go through QRH? Or do you disconnect FDs/AP and level off with known values that we know from memory (3 and 60 works fine) and then go through QRH?

Have done both in the sim, however I am not sure which is the correct one, but the second seems incorrect to me. Instructor didnt tell me anything about that.

Its a stupid habit I have to avoid overspeed warnings when climbing with blocked pitot tube. I complete the procedure and then climb to avoid all that noise in the sim. But dont think thats correct way

[FlightDetent]

It was on an assesment, when years ago the evaluating pilot briefed this for a mid-way case such as you ask:

6° NU / 60% N1, even on the EPR engines, rule of thumb for level flight. This step is embedded in the QRH tables but it takes some time and effort to read that out.

Even today the tables are not the best design, namely the clean table is organized differently from the S+F one.

In real life, I would not hesitate to use 6/60 to stop climbing if that was needed. The SIM may not be the best place to start showing own memory items.

Airbus procedure covers your dilemma well, as it is. Check the blue diagram for decision making from the FCTM.

= ignore/remove FDs, don't change P+P, pull QRH and 'level off for troubleshooting' using the table.

But it is 6/60.
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[Lantirn]

Thanks FD

Was looking at that FCTM page some hours ago.

Haha 6/60 is for GD? Recently I used 4/62 in the sim interpolating from table and worked wonders! 3/60 maybe is for lower altitudes? Have noticed in the actual airplane, but maybe I was fooled, you know sometimes you cant distinguish 3 with 3.5 and if the speed was little higher with lighter GW...idk!

[FlightDetent]

You made me read the books and refresh memory, appreciate the opportunity. My previous post is misleading and mistaken to suggest 6/60 gets you level.

The goal is not to skip or replace the QRH table which is used fly level (pretty damned precise). 6/60 will give you a stable and safe trajectory (residual climb) in all cases, irrespective of weight and configuration, engine, winglet and fuselage length, also at different altitudes.

Exactly the case you inquired: Path is safe but you need to act for A.N.C. while the QRH is figuratively out of reach. A procedural gap which 6/60 will bridge gracefully.

LEVEL FLIGHT INITIAL/INTERMEDIATE APPROACH
A320 wingfence CFM engines 60 t (MLW -10%)
clean cf = 5.5 / 54
config 1 = 6.5 / 58
cnf 1+F = 5 / 58
config 2 = 5.5 / 58
L/G + 3 = 7 / 64

LEVEL FLIGHT INITIAL/INTERMEDIATE APPROACH
A320 Sharklet NEO PW engines 60 t (MLW -10%)
clean cf = 5 / 50
config 1 = 6.5 / 52
cnf 1+F = 5 / 50
config 2 = 5.5 / 52
L/G + 3 = 7 / 56

I got advised 9 years ago; for NEO 5.5/55 looks closer to the original concept. But that defies the idea of remembering just one value. I mean, if 6/60 sounds too much with those engines, try zooming on CLB/10 instead.

The 3/60 you mentioned is not good enough with flaps out, resulting in an undesirable combination of sink and acceleration.

[Lantirn]

Nice refresh FD

The 3/60 is a clean airframe value but you are right. Its not enough for dirty config.

6/60 is a very good value to keep in mind and had never thought it like that!

I had in my mind only clean values. 3/60 for low altitudes and 2.5/78 for high alt cruise.

Good to know, thanks!

[pineteam]

NOT to be used a primary reference in emergency, this is just some parameters I observed during flights. Always apply the memory items in case of emergency.

For A320 and A321 in clean config: I have been playing a game in my head to try guessing what will be the N1 and pitch when I level off and after many observations I came with the following rule of thumb:
FL300 and above: Pitch 2 and 80% N1 will keep you out of trouble. Adding 1% N1 for every 3000 feet higher in case of heavy weight could be consider: For instance if you are cruising at FL 360, target an N1 of 82%. On the NEO, I noticed the N1 is usually higher compare to the CEO so I would add maybe 1% N1 every 2000 feet instead.

For lower altitude: Minus 1% of the N1 for every 1000 feet works fine also. For Instance if I was flying at FL 250, I would target a pitch of 2.5 and a N1 of 75% then FL 100 N1 of 60% and pitch of 4 degrees.. The pitch I would increase by 1 degree every 10 000 feet.
These are just approximate values I observed. The one at high altitude is pretty much spot on. You can have a look next time you fly. =)

[vilas]

What is not clear to me is how you handle that when climbing and passing lets say 10.000

Fly 5° pitch, the thrust is in CLB. After that pull out QRH. Take any altitude above MSA and level out using GPS altitude and using the thrust given in QRH. First maintain altitude then check attitude and adjust thrust as required to get correct attitude. No need to tax the memory. Airbus has now come out with Digital Back Up Speed or the D BUS. Now it's ECAM action.