Autopilot Speed Issues

Hi, I’ve noticed this while flying particular larger jets like 747 or a380. the speed autopilot doesnt really gets me to that speed. its always 0.01-0.02 mach number slower. if i’ve set speed to mach 0.85. it’ll fly at mach 0.83. and it is not that it can’t accelerate further. i see the throttle at 80%. if i turn off autopilot. accelerate manually. then engage autopilot it again slows my speed down.

also with 747 auto pilod. during climb it breaks my vertical speed a lot early than my set cruise altitude. it climbs the last 500 feet at about 100-200 feet per minute.

1 Like

This is just how the program works, it doesn’t always work precisely and all of us are used to it 😉

Sometimes it does that because it is going to change to how you have it before you engage autopilot. It does the same with every aircraft. Nothing to really be worried about.

1 Like

The higher you climb, the lesser you have to adjust your vertical speed. During cruise, headwind might play a role in this. Some people also encourage step climbing.


Both of them, the A380 and the B747, are pretty old and need a rework. These speed issues usually happen when you are heavy, it should fix itself once you get lighter.

1 Like