Boeing Flap Extension
Thread Starter
Joined: Nov 2019
Posts: 25
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From: Sydney
Boeing Flap Extension
Quick query if I may.
Whilst normal flap extension allows speed reduction to the new flap manoeuvre speed before flap is set (unlike non-normal flap extension), must I await the amber band to reduce accordingly before reducing the speed?
Any information would be appreciated.
Whilst normal flap extension allows speed reduction to the new flap manoeuvre speed before flap is set (unlike non-normal flap extension), must I await the amber band to reduce accordingly before reducing the speed?
Any information would be appreciated.
Joined: Dec 2005
Aviation Qualifications: ATPL
Posts: 4,998
Likes: 341
From: Hong Kong
767 here. When extending flaps the biggest effect on the amber band will be from UP to F1 when the slats extend. That takes about 5 seconds whereupon the amber band drops about 40kts. You'd be hard pressed to keep it in the amber band on purpose let alone by accident. Flap maneuver speeds are recommended anyway. Boeing also recommends you set your target speed above MinMan (amber band) but there is no prohibition on flying in the amber band either. Look what happens when you pull speedbrake.
Joined: Sep 2017
Posts: 132
Likes: 31
From: Middle East
The Boeing manuals are pathetically lax on this subject. And in a previous operator, despite the lack of information, some trainers would cry for their mothers if they ever saw anyone fly below any Flap speed. Airbus says it's allowed but not advised in turbulent conditions (obvious stuff).
Joined: Dec 2005
Aviation Qualifications: ATPL
Posts: 4,998
Likes: 341
From: Hong Kong
Agreed. I think the confusion comes from going from steam to digital and giving a wishy washy explanation about how to actually fly the airplane (it's in there but you really have to look for it).
With steam gauges there is no amber band so they created a load of arbitrary (+20, +40, +60 etc) recommended speeds which are easy to follow (unlike the flap maneuver margin chart). They were designed to allow you to safely pull speedbrake at UP,1,5&15, warned of buffetting at F20 (clue!) and prohibited its use at F25/30
When they went to EFIS they had a dynamic amber band which graphically represented where your maneuver speed actually was, which is usually significantly lower than the old recommended speeds and they even included a statement that during normal operations the target speed should be above the Amber. 90% of people refused to let go of the past and stuck to the old way of doing things, rendering the amber band almost pointless, other that as a tool to scare themselves with.
With steam gauges there is no amber band so they created a load of arbitrary (+20, +40, +60 etc) recommended speeds which are easy to follow (unlike the flap maneuver margin chart). They were designed to allow you to safely pull speedbrake at UP,1,5&15, warned of buffetting at F20 (clue!) and prohibited its use at F25/30
When they went to EFIS they had a dynamic amber band which graphically represented where your maneuver speed actually was, which is usually significantly lower than the old recommended speeds and they even included a statement that during normal operations the target speed should be above the Amber. 90% of people refused to let go of the past and stuck to the old way of doing things, rendering the amber band almost pointless, other that as a tool to scare themselves with.
