737NG VNAV anomalies
Several times now when descending in VNAV Path, the aircraft has suddenly defaulted to the Flap limit speed no matter what the altitude or other restrictions inserted (xxx/FLAP) in the speed limit window.
It seems to happen mainly when going direct to the centre fix from some distance and at high altitude. All the decel points disappear and the bug goes to the 'Up' position. No changing of vertical or lateral path seems to make any difference. I have a suspicion it might be associated with changing to VNAV path when descending in Level Change in a Mach Number with IAS higher than the conversion IAS entered into the DES page but I would welcome any enlightenment on the subject.