Flexible V1
Thread Starter
Joined: Jan 2001
Posts: 109
Likes: 3
From: Right hand seat
Flexible V1
I have recently moved aircraft types and am now flying one which allows flex take offs and when programing the autothrottle allows you to choose a V1. What are the advantages of choosing V1 min over V1 max or vice versa? Is it a bit like taking off with more/less flap?
V1 min gives you a shorter TORR and consequently shorter stopping distance but then you are at a lower airspeed after unstick whereas V1 max is the opposite. Should one always choose V1 max on longer runways? Are there any other factors I should be thinking about as well?
Thanks.
V1 min gives you a shorter TORR and consequently shorter stopping distance but then you are at a lower airspeed after unstick whereas V1 max is the opposite. Should one always choose V1 max on longer runways? Are there any other factors I should be thinking about as well?
Thanks.
Joined: Mar 2007
Posts: 95
Likes: 0
From: UK
Check your Vmcg.....In-particular against an artificial increase in V1 to say 120kts in Wet Conditions!! (usually only an issue on mid length R/W's)...
V1 min will decrease your screen height
V1 max will increase your screen height
PERF A.....Both should give you obstacle clearance, but do you really want to reduce your screen height (35') at shorter airlfields....?
V1 min will decrease your screen height
V1 max will increase your screen height
PERF A.....Both should give you obstacle clearance, but do you really want to reduce your screen height (35') at shorter airlfields....?
Last edited by CAT1 REVERSION; 14th January 2010 at 17:03.
Joined: Sep 1998
Posts: 1,615
Likes: 1
From: wherever
unless you have obstacles I would go with MIN every time. Lot's a failed rejected take offs to read about, not very many cases of hitting stuff after take off.
Err on the side of safety if I was you.
Err on the side of safety if I was you.
Joined: Jun 2003
Posts: 156
Likes: 0
From: Madrid
V1 Range
Some Gross wight charts or RTOWs offer the oportunity to operate with a range of V1 when taking off from a runway longer than needed.
V1 max will be limited by ASDA or TORA (if SWY not available)
V1 min will be limited by TODA or TORA (if CWY not available)
The bigger the diference between runway needed and available the wider the range.
Anyhow, V1 must comply with limitations regarding Vmcg and Vmbe.
Prior the take-off only ONE (not a range) V1 must be chosen.
A very nice explantion can be found on "Getting to grips with aircraft performance" from Airbus. Look at SmartCockpit - Airline training guides, Aviation, Operations, Safety at Flight OPS/performance/ "Understanding V1 Range" from Boeing.
REGARDS.
V1 max will be limited by ASDA or TORA (if SWY not available)
V1 min will be limited by TODA or TORA (if CWY not available)
The bigger the diference between runway needed and available the wider the range.
Anyhow, V1 must comply with limitations regarding Vmcg and Vmbe.
Prior the take-off only ONE (not a range) V1 must be chosen.
A very nice explantion can be found on "Getting to grips with aircraft performance" from Airbus. Look at SmartCockpit - Airline training guides, Aviation, Operations, Safety at Flight OPS/performance/ "Understanding V1 Range" from Boeing.
REGARDS.
Fleet Manager
Joined: Apr 2001
Aviation Qualifications: ATPL
Posts: 7,448
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From: various places .....
Some interesting ideas floating around in this thread .. first ..
V1 min gives you a shorter TORR and consequently shorter stopping distance but then you are at a lower airspeed after unstick whereas V1 max is the opposite.
...can we revisit and provide some further comment on these thoughts ?
V1 min gives you a shorter TORR and consequently shorter stopping distance but then you are at a lower airspeed after unstick whereas V1 max is the opposite.
...can we revisit and provide some further comment on these thoughts ?
