Gear extention Alt limit?

[badrace]

Similar to flaps operating limit ,why is there a limitation on maximum gear extention , can't see any reason with critical mach .Wondering why.

[NSEU]

(Edit) Sorry, misread the question

Regards.
NSEU

[Metro man]

Possibly it may result in adverse handling characteristics. With no real reason to extend the gear at high altitude, assuming the aircraft can meet emergency descent requirements without it, the manufacturer may have just imposed the limit for certification purposes.

[capt. solipsist]

Badrace,

The limitation is mostly for the landing gear door. Notice how much faster you can go after the gear has been fully extended (and doors have closed!)

:ok:

[FE Hoppy]

Not all aircraft have a maximum altitude gear extension limit. Some may even require gear extension in order to meet the emergency descent requirements.

If there is an altitude limit I would assume it's due to stability and control requirements.

[capt. solipsist]

Sorry, must've misread the question, i thought you were referring to speed limits. :O

[Intruder]

No altitude limit in any model of the 747. Gear down is one option for emergency descent from any altitude, as long as speed is <M.82.

[Denti]

Same on the 737.

[badrace]

Thanks!There are limitations in FCOM limitation sections indicates A320 max Alt for gear extention is 25,000ft, A330 is 21,000ft. Handling qualities must be a major consideration,also I'm guessing the other reason is no certification requirement beyond these levels.

[Runaround Valve]

Slight thread drift here, but an historical item.
The early Boeing 747 aircraft had another position on the landing gear selection lever. It was 'wing landing gear'. This gear could be lowered by itself for drag. The selection was later removed as the wing and landing gears shared a common wheel well. The airflow into the wing gear wheel well with only the wing gear down would blow the body gear doors open.

[badrace]

Thanks for the history,but still there should only be speed or mach limitations here,and I didn't see Alt limitations on any boeing or MD aicraft ,only on airbus .