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-   -   Positive Rate (https://www.pprune.org/tech-log/633473-positive-rate.html)

safetypee 28th Jun 2020 06:09

V1 - Engine failure - Rotate - … …
 
With the various views and procedures above, how, if at all, are they changed - applied in the event of an engine failure just after V1.

deltahotel 28th Jun 2020 09:44

Can’t help thinking there’s some over complicating going on. Can’t answer for the Airbus, but Mr Boeing’s FCTM states ‘Retract the landing gear after a positive rate of climb is indicated on the altimeter.’ No more, no less.

Yes there are secondary and peripheral clues - the click of the lever lock, the houses getting smaller etc but Mr Boeing is the master of the art of keeping things simple.

safetypee - the wording in the FCTM is identical for the EFTO case.

rgds

vilas 28th Jun 2020 10:43

With 50% loss of thrust the acceleration is less so rate of rotation needs to be slower and to a lesser attitude 12.5° in Air bus. Other than that everything else is same. RA and VS increasing raise the gear.

Denti 28th Jun 2020 12:32

Just make sure it is not a momentary spike on the V/S, that could end very badly indeed... And yes, seen it enough in the SIM.

hoss 28th Jun 2020 21:45

The EK777 crew may have seen a positive rate on their altimeters but did they ‘sense’ (sight, sound and touch) the G/A thrust coming on. Did it feel right.

Maybe I’m too over cautious with the positive rate call but I’m glad I take 1 second longer than the fastest pilot in my company.

Uplinker 29th Jun 2020 09:32

The snag with the SOP of "positive RATE", is that the only cockpit instrument that gives a rate reading is the VSI/IVSI. Concentrating on the rate parameter might cause some pilots to only look at the rate indication, which might be false.

As the aircraft rotates, the static ports - usually situated around the front of the aircraft - will climb, even when the main gear is still on the runway, so this indication does not necessarily mean that the aircraft is climbing. Ditto the altimeter.

The Rad Alt aerials - on Airbus situated well behind the main gear - will inititally show a descent when the aircraft rotates.

Only when all three: VSI, Altimeter and Rad Alt are showing positive or increasing readings, can one be sure that the whole aircraft is climbing up above the runway. Take a moment to be sure all three indications are solid and not a momentary glitch, before calling positive CLIMB.

Another good reason for checking three instruments instead of one or two, is to check against a faulty instrument. All three should agree the aircraft is actually going up ! :ok:

Vessbot 29th Jun 2020 10:08


Originally Posted by Uplinker (Post 10824252)
The snag with the SOP of "positive RATE", is

...

Take a moment to be sure all three indications are solid and not a momentary glitch, before calling positive CLIMB.

Your valid point about overreliance on one instrument aside, you should use the callout verbiage that your SOP specifies.

vilas 29th Jun 2020 10:14

Identifying +ve climb is not a big issue. The real problem is understanding priorities. Gear is not something that is to be got rid of as quickly as possible. I can't think of any incident where raising gear quickly or out of turn saved a disaster. It's other way round. In EK case if gear wasn't retracted aircraft wouldn't have been written off. On GA it's power, pitch, flaps then gear. On a low GA you hit TOGA, small change of pitch flap gear are left as they are till you are climbing away. No attempt is made to avoid ground contact because gear is the only part that can take impact load. Tail strike is more damaging.

FlightDetent 29th Jun 2020 10:53


Originally Posted by Uplinker (Post 10824252)
Only when all three: VSI, Altimeter and Rad Alt are showing positive or increasing readings, can one be sure that the whole aircraft is climbing up above the runway.

That's pushing personal / company habits too far. Sinner like me can tell, as long as it is other people who are guilty and not yours truly. :)

And also factually incorrect.

Pugilistic Animus 29th Jun 2020 11:20

It's a positive rate when the dog on the flightdeck starts trying to bite your hand
:}

safetypee 29th Jun 2020 12:40

Dead Dog
 
dh, #22, :ok:
Same procedure checks and calls, but with an engine failure and a performance limited departure, the timing of the checks and altitude of gear retraction need to change.

vilas, 'Gear is not something that is to be got rid of as quickly as possible'; so what triggers the change in thinking with engine failure, … the dog,

but PA's dog dies with engine failure; surprise of the event, forget, revert to everyday habit.

transducer 7th Jul 2020 13:28

The Airbus FCTM>Procedures>Abnormal and Emergency Procedures>ENG>Engine Failure after V1, states the following under the "WHEN SAFELY AIRBORNE" heading:
With a positive rate of climb and when the radio height has increased, the PM will call "positive climb". This will suggest to the PF for landing gear retraction.

RVF750 7th Jul 2020 18:04

There are VERY FEW things on the flightdeck where rushing helps at all. In sim sessions, it's always rushing that causes issues. Even the swing of the normal V1 cut isn't immediate in a hi-bypass jet. Just take it easy, check and double check and satisfy your inner SA all is as it should be, then act.

It's always worked for me.

Mad (Flt) Scientist 8th Jul 2020 00:05

Just out of curiousity, has there ever been an incident (let alone accident) where a crew dawdling in raising the gear (but doing so eventually) has caused the problem? I can't offhand think of one.

The reality is that even single engine performance has margins built in, and considers a case usually much worse than the case of the day. I'd be really shocked if an extra, say, 5 seconds in initiating gear retraction in any remotely routine OEI condition represented a meaningful safety reduction.

Check Airman 8th Jul 2020 03:09


Originally Posted by Mad (Flt) Scientist (Post 10831528)
Just out of curiousity, has there ever been an incident (let alone accident) where a crew dawdling in raising the gear (but doing so eventually) has caused the problem? I can't offhand think of one.

Define "eventually":E.

I can't find an actual report on this incident.

https://www.ajc.com/news/national/ai...3367aYfQHffMJ/

vilas 8th Jul 2020 03:51


I can't find an actual report on this incident.​​​​​​
The link you posted is good enough. That's all happened. Fortunately while landing at the diversionary airport while putting the gear down they realized the gear was already down and left it down. Otherwise had they acted on it mechanically that just change the existing status then it would have been more interesting.

Goldenrivett 8th Jul 2020 09:20

Action Slip
 

Originally Posted by vilas (Post 10831596)
Fortunately while landing at the diversionary airport while putting the gear down they realized the gear was already down and left it down.

There is a recognised human error called "action slip". If you have ever tried to make a cup of tea by pouring the boiling water into the tea caddy rather than the tea pot or put your keys down in an unusual place so you can't locate them - then you have performed an action slip. If you haven't yet - then most probably you eventually will.

A more serious action slip is moving the flap lever instead of the gear lever. G-EZOZ

Usually an alert crew will recognise the error and fix the problem. Sometimes if overwhelmed by other distractions e.g. overspeed warnings, "terrain ahead pull up" etc. then the action slip of moving the gear lever in the wrong direction may (did) go unnoticed. But WTF did the crew of PIA 8303 not GA at 500 feet?

Check Airman 8th Jul 2020 14:53


Originally Posted by Goldenrivett (Post 10831814)
There is a recognised human error called "action slip". If you have ever tried to make a cup of tea by pouring the boiling water into the tea caddy rather than the tea pot or put your keys down in an unusual place so you can't locate them - then you have performed an action slip. If you haven't yet - then most probably you eventually will.

Ah. So that’s what that’s called. I always thought it was called “getting older”. Really can’t relate to the tea example though. I’m not sufficiently British ;)

hans brinker 8th Jul 2020 18:04


Originally Posted by Check Airman (Post 10831579)
Define "eventually":E.

I can't find an actual report on this incident.

https://www.ajc.com/news/national/ai...3367aYfQHffMJ/



Originally Posted by vilas (Post 10831596)
The link you posted is good enough. That's all happened. Fortunately while landing at the diversionary airport while putting the gear down they realized the gear was already down and left it down. Otherwise had they acted on it mechanically that just change the existing status then it would have been more interesting.

Well, in their "defense", they had two working engines....
Also for what happens with just "changing the existing status", see the Karachi thread (IMHO).

vilas 9th Jul 2020 02:32

Goldenrivette
I would consider it as a Pavlovian conditioned reflex. In 70s there was an incident of Russian fighter jets landing gear up. The aircraft came in for landing the gear was seen to be down but had to go round. In second approach landed wheels up. In inquiry pilot was sure he had lowered the gear in downwind. Actually he had forgotten to raise the gear after missed approach and in downwind he thought he is putting it down but in reality he had raised it. PK8303 actually confirmed a lot of human factors.


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