Roll rates & gear up selection times

[Boyscout]

Searched everywhere (you'll probably correct me) and can't find any info on these couple.

Roll rates: what do performance boffins (engineers) work on re: roll rate into a turning departure? I have seen many variations on this theme.

Also, how long do you have until you must select the gear up after an engine failure at V1? Obviously the 2nd segment is dependent on this & it must be certified, but what is accepted practice? (obviously staying clear of granite clouds is accepted).

Anyone bored & got a link?

Cheers BS :hmm:

[Rainboe]

I think it is pretty well standard procedure that the first item to be actioned on lift off is 'positive climb-gear up'. It reduces drag and will only be forgotten if you don't do it straight away and get it out of the way. It is advisable to get the aeroplane climbing away at safe speed bearing in mind terrain before anything else is done. Taking it slow, both pilots positively identify the engine and problem followed by Handling pilot calling Fire checklist, and non-handler actioning it. Then you have flap clean-up and conversing with ATC and decision on what to do next. You lose points if the gear is still down at that stage, so very important to do that first of all.

As for roll rate, I have never heard of a minimum or maximum figure. You just roll comfortably into the turn at your own rate.

[Boyscout]

Thanks for your time Rainboe

Yeah my point exactly. Bit of a no-brainer that you need to get the wheels up to perform, however seeing as everything else we seem to do these days is quantified, no doubt there are some test pilots out there that can give us a figure as to the maximum time until you action gear lever up?!

I roll at my own rate too (5 deg per sec or so onto an escape heading or thereabouts), but I have seen so many variations on the theme there has to be a standard somewhere?

AUS CAO 40.2.1 says nothing about it so I guess that's why I pass, but anyone else got any info?

Take care mate

[Rainboe]

I'd be very surprised if any figure is quoted anywhere. You should be completely occupied with establishing which way to turn, and how far, and flap/acceleration configurations to worry about aiming for x degrees/second. It's just one of those common sense things!

[BOAC]

Boyscout - might be better if you deleted this thread and reposted on 'Flight Testing' where I have no doubt someone will know the answer.

[CaptainSandL]

Dont forget guys it is an accepted & approved procedure to leave the gear down after departure for cooling if required. I have never seen any performance correction figures for this but I suppose you could use gear down (ferry) performance for the 4 segments and then you would be covered.

S&L

EDIT Sorry I missed the bit about "after an engine failure at V1?" obviously you would bin the cooling and raise the gear. No idea how quickly you are supposed to do this.

PS If it helps, we time the gear retraction at 130kts on airtests and it has to be up within 10secs (737). This obviously takes no account of how long it takes for you to remember to raise it when the heat is on!

[john_tullamarine]

(a) I've no recollection of ever seeing a nominal roll rate declared for turning departures. From a practical point of view, the trapezoid splays give enough fat to cover minor variations within a "normal" band of roll rates for a given aircraft. Unless the procedure calls for something different, the presumption will be 15 deg bank for the OEI case.

(b) the AFM will declare the presumed point (time) at which gear is selected up and the sums are based on this presumption. Can't recall ever seeing any variation for OEI/AEO declared.

[FE Hoppy]

AMC 25.111(b)
Take-off Path
1 Rotation speed, VR, is intended to be the speed at which the pilot initiates action to raise the nose gear off the ground, during the acceleration to V2; consequently, the take-off path determination, in accordance with CS 25.111 (a) and (b), should assume that pilot action to raise the nose gear off the ground will not be initiated until the speed VR has been reached.
2 The time between lift-off and the initiation of gear retraction during take-off distance
demonstrations should not be less than that necessary to establish an indicated positive rate of climb plus one second. For the purposes of flight manual expansion, the average demonstrated time delay between lift-off and initiation of gear retraction may be assumed; however, this value should not be less than 3 seconds.

[Boyscout]

Thanks lads

New it would promote some discussion & I won't post it on the Test Pilot site as I will not understand the response. If I find anything else out I will add to this later.

Stay out of the trees

BS