737NG Engine IN-Flight Start Envelope.
Joined: Jun 2000
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From: last time I looked I was still here.
I assume you are talking about the windmill start envelope. I suspect this is not the NG family as -800 has a different speed. 281kts seems very picky: why not 280; it's easier to remember. Why make an easy job difficult under stress? Anyway the need for speed is to keep the engine turning fast enough to have sufficient air flow to 'jump start' the motor. Slower speed would require a hand crank.
Joined: Apr 2010
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On your inflight start enveloppe ,from Fl240 to FL150 the speed of 281 kts is the minimum to be in the windmill area.
Below FL 150 you need a minimum of 300 kts to be within the in flight start enveloppe for windmilling.
The 281 kts is written on the chart and it is for the NG.
Maybe that speed represents the speed at which a successfull relight was demonstrated,again it says successfull starts may be obtained outside of the enveloppe but not assured
like any other would be...
Below FL 150 you need a minimum of 300 kts to be within the in flight start enveloppe for windmilling.
The 281 kts is written on the chart and it is for the NG.
Maybe that speed represents the speed at which a successfull relight was demonstrated,again it says successfull starts may be obtained outside of the enveloppe but not assured
like any other would be...
Joined: Mar 2001
Posts: 4,563
Likes: 35
From: I wouldn't know.
Interesting, the envelope in my QRH shows 281kts at a pressure altitude of 24.000ft, but rising in a linear fashion to 300kts at 15.000ft.
I remember that the envelope changed in 2011 once we got the -7BE variant on the line, it used to be somewhat different before that.
I remember that the envelope changed in 2011 once we got the -7BE variant on the line, it used to be somewhat different before that.
Joined: Jun 2000
Posts: 4,507
Likes: 4
From: last time I looked I was still here.
There are pilots I teach/check who can not fly +/- 5kts on approach, so heaven help them trying to fly 281 kts with a double engine failure. Give it +/- 20kts and they have a chance. Get real guys.
Joined: Apr 2010
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RAT5,
Its not about being able to do it or not.
by the way with loss of both engines,captain should become PF and if your airline captains cant pitch for an airspeed within 10 kts then god have their soul and good for you as you have more teaching to do.
Please go and tell boeing to get real then and change the info (speeds) on their published inflight start enveloppe.
Its not about being able to do it or not.
by the way with loss of both engines,captain should become PF and if your airline captains cant pitch for an airspeed within 10 kts then god have their soul and good for you as you have more teaching to do.Please go and tell boeing to get real then and change the info (speeds) on their published inflight start enveloppe.
Last edited by de facto; 10th March 2014 at 12:39.
