Autopilot and 500 feet AGL?

[multi_engined]

I was just wondering why aircraft have to be at a minimum of 500 feet on climbout before the left command autopilot can be engaged? Is it just there to be a safety buffer or?

[Old Smokey]

Unless it's a company SOP or compliance with your local regulatory authority's requirements, it will all come back to the degree of redundancy associated with your Auto-Pilot.

You did mention the LEFT command auto-pilot, which would infer to me that you're engaging a single, no backup system, thus, there's no automatic redundancy if it should fail. Perfectly OK at higher altitudes where you can safely intervene within within a few seconds if failure occurs, but not so acceptable at low level.

Aircraft such as the B777 have a single Auto-Pilot switch, which engages a single A/P, but has the other 2 A/P's standing by to take over if internal logic cross checking indicates that the primary A/P is acting spuriously.

Regards,

Old Smokey

[ETOPS]

Boeing 777 has 200 ft minimun engage alt and 747-400 has 250 ft.

What type are you referring to, multi_engined?

[multi_engined]

More the Boeing fleet - 747-400, 767, 777 etc...

Can you please clarify I am correct in saying 250ft is the minimum height to engage the autopilot after takeoff? In the 767 the pilot normally waits till passing 400-500 feet before engaging the autopilot...

Are there any difference in minimum heights for the Airbus fleet?

Thanks for the replies!

[FlapsOne]

A320 family - min 100ft/5 secs after lift off.

[ETOPS]

Can you please clarify I am correct in saying 250ft is the minimum height to engage the autopilot after takeoff?

Yes - that's correct.........

[springbok449]

A340 family is like A320s 100ft or 5 secs after lift off...