Altitude stuck, doesn't go up or down, even with ALT hold selected

[myoung 1]

The altimeter is correctly set and the wind is loaded, the aircraft is at 660.3 GW (LBS) and there's 64.6% of fuel left.

I'm trying to climb to the cruise altitude of 38,000ft but it's stuck at 36,760ft.

I rolled down the altitude to 36,000ft and changed the cruise altitude on the VNAV page, but it stayed at that altitude, even if I select the ALT hold button, I took off autopilot and flew manually to 38,000ft and then engaged autopilot again, but it descends back down to the 36,760ft altitude.

I tried switching between the VNAV and the ALT hold buttons, but they both keep the aircraft at 36,760ft.

There are no warnings or cautions being shown, both engines were at climb thrust until it got stuck at 36,760ft, at which point I put them into CRZ.

Both flight director switches are on, and the FO side and the backup display both show the same readouts.

I'm flying with ASN set to historical and sim time on the 777-300ER, the same as last flight which climbed fine.

Any help is appreciated.

 

Mike Young

[scandinavian13 5,192]

Any help is appreciated.

 

If the plane levels off, you need to hit ALT INT before it's going to act on any change to the MCP.

 

Say you set 10000, but your CRZ is FL350. If you don't get your further climb instruction and the plane levels off at 10000, once you get instructed to climb higher, you roll the selected altitude up to whatever they assigned, and hit ALT INT (in the 777, this is the center of the altitude wheel).

[myoung 1]

Can't believe I didn't try that as it fixed the problem, thanks.

 

Mike Young

[scandinavian13 5,192]

Can't believe I didn't try that as it fixed the problem, thanks.

 

Welcome! Sometimes, it's (luckily) the simple things.