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Landing gear retraction time

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Landing gear retraction time

Old 21st Mar 2020, 12:54
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Landing gear retraction time

My aircraft’s flight manual says that landing gear retraction time increases during go around by approx 3 seconds which will not impair the aircraft’s performance. Why will the retraction time increase ?
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Old 22nd Mar 2020, 01:26
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Hydraulic or electrical?

If hydraulic, it might be that while retracting the flaps, there is less power for the wheels.
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Old 22nd Mar 2020, 08:50
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The drag of the extra speed you might have perhaps?
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Old 22nd Mar 2020, 10:37
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You don't say if this is with all engines operating or with an engine out in which case you might have a pump inoperative too.
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Old 23rd Mar 2020, 09:53
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Would help if you told us what type of aircraft it is as well.
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Old 2nd Apr 2020, 08:09
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Thanks for the reply.
The undercarriage is hydraulically operated however electrically actuated. Plus, flaps selection will be generally post undercarriage retraction.
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Old 2nd Apr 2020, 08:12
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Hey , thanks for the reply.
The speed after a go-around at which the undercarriage is retracted may be the same as the speed after a normal take-off at which the undercarriage is retracted.
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Old 2nd Apr 2020, 08:19
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It's an An-32.
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Old 2nd Apr 2020, 08:24
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LG Retraction time

Hey, thanks for all the answers.
I would clarify some of the questions.
Its an An-32 ac (twin engined) in which the LG is hydraulically operated and electrically actuated. The speed at which a go-around is done and LG retracted may be almost same as the speed after a normal take-off and LG retracted thereafter. The case being talked about is of a both engine operating one. The undercarriage is retracted in the opposite direction of the flight i.e. rearwards.
Thanks.
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Old 1st May 2020, 07:07
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Did you find out the reason for the 3-second difference in retraction time, between the T/O and the G/A scenarios? This presumes both engines are operating as normal in both cases? Curious.
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Old 1st May 2020, 07:20
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Perhaps as the aircraft accelerates more rapidly during the go-around, air loads on the main landing gears doors slow the retraction sequence? The doors open outwards, the landing gear retracts when they've opened, then the doors close inwards. During both door movements they will experience a lateral angle attack with the airflow, leading to some drag against door movement slowing the retraction cycle.
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Old 2nd May 2020, 04:32
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Upon takeoff you will start retracting the gear after - obviously - having rotated.

When initiating the go-around with all engines running you would wait for positive rate before raising the gear, situation not much different.

However in the worst case, you are going around from a OEI situation and you will be retracting the gear while rotating, with extra g-load, that's extra gear weight to be pulled in, and may take longer.

?

jr
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