Originally Posted by
B737SFP
Some do... Some don't !
I don't... Can't see a reason for waiting.
The "waiting thing" is most common among pilots with a 737-300 background !
If I remember correctly, selecting the flaps without having the landing gear down and locked (green lights) on this type would sound the "Landing Gear Configuration Aural Warning" (which was really annoying), but it could be easily muted (just as on the NG)
In the 737 NG procedure, the PF issues the combined command:
“GEAR DOWN, FLAPS 15”, and the PM carries out the selections.
However, the key procedural intent remains unchanged:
The
gear lever selection and flap 15 selection are still intentionally sequenced with a verification barrier in between, even if the callout is combined.
The PM:
- selects gear DOWN
- confirms three green landing gear indicators
- then selects flaps 15
Why Boeing structures it this way:
The landing gear lever position is only a
command to extend, not confirmation of status. The system can still be:
- in transit
- asymmetrically extended
- or affected by a malfunction (gear disagree / unsafe indication)
So the
three green lights are the required positive confirmation of “down and locked” status before the configuration progresses.
Flap 15 is part of the
landing configuration build-up, and Boeing’s intent is to ensure the aircraft is in a
verified stable configuration state before further increasing drag and changing energy management characteristics.
Bottom line:
Even though the PF issues a single combined call, the system logic and SOP intent still require:
gear status confirmation (three green) before completion of the landing configuration to flaps 15.