February 7, 20188 yr I was cruising along happily and suddenly I noticed a massive drop by my lnav speed bug. I haven’t flown this aircraft in quite some time and want to know why this happened? It caused me to miss the next descent checkpoint. Is this new? I don’t remember it from before. I was attempting to descend to fl 111, but it wouldn’t go down while the speed was decreasing. I’m assuming this can be changed in the fmc? Pattick Boynton
February 7, 20188 yr Hi, Most likely a speed restriction along the way. Check in the leg page to find that restriction. The pitch mode whether it is VNAV PTH, VNAV SPD or FLCH will reduce the descent rate to bleed to the speed in order to meet a speed restriction. Also check the FMA to confirm in which autothrottle and pitch modes are active. What STAR did you follow? Romain Roux Avec l'avion, nous avons inventé la ligne droite. St Exupéry, Terre des hommes.
February 7, 20188 yr Author None though there might have been a waypoint on the flight that is part of a star? I’ll check things but as I said it’s been some time since I flown. Patrick Boynton
February 7, 20188 yr 15 hours ago, Dragonmount said: None though there might have been a waypoint on the flight that is part of a star? I’ll check things but as I said it’s been some time since I flown. Patrick Boynton Patrick, I urge you to always look at the terminal procedures charts (arrivals, departures and approaches) before flying them. You don't want surprises. Dan Downs KCRP
February 8, 20188 yr Additionally, you are the pilot. Speed or altitude restrictions do exist and it‘s your responsibility to match them. If the magenta line modes (LNAV/VNAV) cannot handle them (the 737 is a slippery airplane) then reach up to the MCP and use less automated modes like VS. Or use the spoilers, flaps, gear if necessary. Or violate the restrictions, you won‘t be executed for a few knots more.. ,
Archived
This topic is now archived and is closed to further replies.