Gear Down In The Turn
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Gear Down In The Turn
Just wondering why putting the gear down in a turn is not good for it. It doesn't say anything in the POH about not putting the gear down in a turn but many people say don't do it but can't seem to give a good clear reason why.
Any suggestions?
MK
Any suggestions?
MK
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Interesting query! Never been suggested to me that it's 'not good' for anything and it is something I do -helps stabilise the speeds in the turn I find. Definitely interested in conflicting (or supporting) opinions!
What airframe specifically?
What airframe specifically?
It's often thought that the likelyhood of a sideslip in a turn, or entering a turn, can lead to excessive lateral airloads on the gear & doors while in a transient state ie not locked up, and not locked down and gear doors open that would normally be closed at the completion of an extension or retraction cycle.
Whether that's the case or not is open to conjecture. I could argue that the pilot's skill should be such that unintentional sideslips don't occur, whether or not the unlocked gear system is sensitive. On the other hand, I've never seen a flight manual or POH that prohibits** extending the gear while turning or sideslipping. I've seen a few that caution against sideslipping for extended periods, but not for gear reasons.
**Slight correction due to a later comment below: The Aerostar's manual says it's not recommended, as best I recall. I don't *think* it says prohibited. Maybe it uses 'avoid' or similar language.. Haven't touched one in over 10 years. Perhaps someone with access to a POH would post the exact wording?
Whether that's the case or not is open to conjecture. I could argue that the pilot's skill should be such that unintentional sideslips don't occur, whether or not the unlocked gear system is sensitive. On the other hand, I've never seen a flight manual or POH that prohibits** extending the gear while turning or sideslipping. I've seen a few that caution against sideslipping for extended periods, but not for gear reasons.
**Slight correction due to a later comment below: The Aerostar's manual says it's not recommended, as best I recall. I don't *think* it says prohibited. Maybe it uses 'avoid' or similar language.. Haven't touched one in over 10 years. Perhaps someone with access to a POH would post the exact wording?
Last edited by Tinstaafl; 9th Jun 2009 at 05:35.
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Interesting, thanks Tinstaafl -I'd certainly be interested in any qualitative studies or further information available if you know of any?
I was always told that it is not good form, for the reasons given above - ie lateral loading on the doors in transit.
I generally drop the gear before turning base and avoid cycling the gear in a turn - but if I need to then so be it. There is nothing in the POH to indicate that I shouldn't.
Dr
I generally drop the gear before turning base and avoid cycling the gear in a turn - but if I need to then so be it. There is nothing in the POH to indicate that I shouldn't.
Dr
Last edited by ForkTailedDrKiller; 9th Jun 2009 at 04:20.
It's the same theory as reducing limit speeds, by operating gear and flap say 10 kts less than the limit rather than taking it at the limit should reduce componant wear. Selecting gear during the turn is the same, side air loads and increased load factor will all place a greater strain on the doors, pumps and actuators.
During the turn how is 1g maintained and therefore no increased load factor balanced or not.
The millitary reason for gear down turning base may differ slightly from civil reasons.
The millitary reason for gear down turning base may differ slightly from civil reasons.
POH
Just follow the POH. The Aerostar POH says not to do it, as it can rip the doors off.
I wouldn't worry about it if it is not in the POH. Just ensure the turn is balanced.
JT
I wouldn't worry about it if it is not in the POH. Just ensure the turn is balanced.
JT
Not if the turn is balanced, should be same as straight balanced flight, military operations pop the gear in the base turn.
My memory is not that good, but when I flew Barons for a PNG operator I am sure we had a note in our manuals prohibiting lowering the gear in a turn.
It wasn't in the manual on any of our other types, so I always assumed it was based on info from the manufacturer.
It wasn't in the manual on any of our other types, so I always assumed it was based on info from the manufacturer.
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Dunno why you would turn out of balance and it is exceedingly difficult to "pull" excessive "G" in a desending turn at speeds that would allow gear extension.
In any event as long as everything is in balance the gear should extend without any side loads.
There is nothing that might stop flap extension in the same circumstances.
However if the AFM/POH prohibits either then it is not smart to ignore the prohibition.
Most higher performance military approaches are a continuous descending turn during which the airframe is made progressively "dirty" and slowed progressively to final approach speed, this is so good visibility of the circuit is maintained and the approach is tight and safe.
In any event as long as everything is in balance the gear should extend without any side loads.
There is nothing that might stop flap extension in the same circumstances.
However if the AFM/POH prohibits either then it is not smart to ignore the prohibition.
Most higher performance military approaches are a continuous descending turn during which the airframe is made progressively "dirty" and slowed progressively to final approach speed, this is so good visibility of the circuit is maintained and the approach is tight and safe.
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Landing gear down in the turn
If you are in balanced flight (should be) in the turn and the applicable aircraft manual does not limit it, then it would be okay.
In my time it was the side load issue that was the main reason for the caution.
Tmb
In my time it was the side load issue that was the main reason for the caution.
Tmb
Dunno about that, Joker 10 - what types are you talking about?
Gear is usually lowered on a straight downwind leg for most military types I know unless it's a spiral-type PFL.
Gear is usually lowered on a straight downwind leg for most military types I know unless it's a spiral-type PFL.
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Landing gear down in the turn
Just wondering why putting the gear down in a turn is not good for it. It doesn't say anything in the POH about not putting the gear down in a turn but many people say don't do it but can't seem to give a good clear reason why.
Any suggestions?
MK
Any suggestions?
MK
Quite simply.....Once upon a time at an airport not far away a lowy inexperienced grade 3 instructor who thought that they were an undiscovered test pilot came up with this "rule" and imparted their wisdom on a hapless student who didn't know any better, who(m) in turn became a low experience instructor armed with this superior knowledge who trained somebody, who became a CFI, who then made it law.
joe crazyhorse,
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Nothing to do with "side loads" in the turn - you get those in the straight and level too.
The only thing different about turning flight, from the point of view of the undercarriage, is the load factor.
If the undercarriage weighs 50 kg under straight and level 1g conditions, then it can weigh, for example, 60-70 kg in a turn.
If the POH prohibits it, that is because either:
1. The manufacturer believes that, over time, damage may occur to the airframe or undercarriage (due to the extra stresses incurred by extension/retraction during turns), or
2. Extension whilst turning was never trialled during certification flight tests.
This answer, by Martin.Sacklage illustrates the situation perfectly:
psycho joe wins the prize for best explanation to why "many people say don't do it but can't seem to give a good clear reason why."
The only thing different about turning flight, from the point of view of the undercarriage, is the load factor.
If the undercarriage weighs 50 kg under straight and level 1g conditions, then it can weigh, for example, 60-70 kg in a turn.
If the POH prohibits it, that is because either:
1. The manufacturer believes that, over time, damage may occur to the airframe or undercarriage (due to the extra stresses incurred by extension/retraction during turns), or
2. Extension whilst turning was never trialled during certification flight tests.
This answer, by Martin.Sacklage illustrates the situation perfectly:
... we used to dump the gear when turning onto base under a higher than 1 G load as they were spring activated and this helped them to extend. Helps with issues in extending them.
Last edited by FGD135; 9th Jun 2009 at 09:55.