Endurance And Gouges

It seems to me that power pilots seeking best endurance should avoid using an autopilot. I understand that autopilots operate elevators rather than the throttle. I've often wondered why one might slow their plane in sink, using up elevator, and spend more time there.

Editorial Staff

Tuesday, March 15, 2016 at 12:00 AM ET

Verified

Key Takeaways:

A reader questions the efficacy of general aviation autopilots for maximizing endurance, noting their control over pitch (via trim) rather than throttle, which can lead to inefficient flight profiles in changing air conditions.
A critical safety concern is highlighted regarding Garmin VNAV functions, specifically their default altitude setting to Mean Sea Level (MSL) instead of Above Ground Level (AGL), which can inadvertently lead to Controlled Flight Into Terrain (CFIT) accidents.
There is a debate on using nose-up trim during landing flare; one pilot advocates it for smoother touchdowns, while the magazine emphasizes the safety risk, particularly the potential for a stall during a subsequent go-around due to excessive nose-up trim.

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A very good article on endurance (“Less Power for More Range,” March 2016). I have not flown with an engine for many years. But I am an active, current and employed glider instructor.

It seems to me that power pilots seeking best endurance should avoid using an autopilot. I understand that autopilots operate elevators rather than the throttle. I’ve often wondered why one might slow their plane in sink, using up elevator, and spend more time there. Conversely, speeding up in rising air with pitch down, minimizing their time in lift. Endurance to me means keeping as much total energy (potential and kinetic) as possible.