V1 engine out procedures
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V1 engine out procedures
Dear All,
If you have an engine failure (at 20 knots below V1) and continue with the one engine inoperative takeoff, will the aicraft, (when it reaches V2) be 35' feet above the end of TODA?
If you have an engine failure (at 20 knots below V1) and continue with the one engine inoperative takeoff, will the aicraft, (when it reaches V2) be 35' feet above the end of TODA?
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20 Kts below V1 will probably put you close to or possibly even below VMCG in a number of scenarios. Is there more to this concept than you are sharing with us at the moment?
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V1
You will probably never reach V2-the earth simply is not that large.
Please do not try this at home or anywhere else!
Please do not try this at home or anywhere else!
Last edited by ARENDIII; 4th Dec 2007 at 15:03. Reason: Spelling
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Very good points made so far. However, just to throw something else into the mix -
Say for example you're flying into cold northern Norway airfields and you select a Go - No go speed of say 80 knots (when the actual V1 is around the 120 mark). What would you do then if you and an engine failure at 100 knots?
I personally would stop as the perf is calculated however, would it be wise with a runway contaminated. Clearly the braking action must be better or the same than MP - MP - MP.
L Met
Say for example you're flying into cold northern Norway airfields and you select a Go - No go speed of say 80 knots (when the actual V1 is around the 120 mark). What would you do then if you and an engine failure at 100 knots?
I personally would stop as the perf is calculated however, would it be wise with a runway contaminated. Clearly the braking action must be better or the same than MP - MP - MP.
L Met
Why would you "select a Go-No go" speed of 80 kts when V1 is 120? V1 is adjusted for slushly runways. If the numbers don't work for the runway, lighten the load. If they still don't work, go to the hotel.
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This is a useful thread as it goes to the heart of the delta between the artificially constrained world of certification and the dirty real world of ice, slush, fatigue, etc., etc. ..... at the end of the day, commanders are paid to make judgement calls ... if your level of conservatism is inadequate on the day, expect to be called to justify your actions at the enquiry.
An easier, less stressful, life is enjoyed by bank clerks ...
As a far wiser commander observed when I was but a new F/O on a day of much thunder, lightning, low minima, etc. .. " at the aeroclub, they wouldn't let us go flying .. now they make us go ". This is one of the worries associated with a general deskilling of the flying workforce ...
In respect of the initial question, if
(a) Vmcg is not a problem
(b) there is adequate spare runway to accommodate the (possibly quite significant) ground run delta
(c) Vr is respected
(d) rotation rate is similar
then, for the same T/W, the speed at screen will be very similar for the V1 and V1- cases.
An easier, less stressful, life is enjoyed by bank clerks ...
As a far wiser commander observed when I was but a new F/O on a day of much thunder, lightning, low minima, etc. .. " at the aeroclub, they wouldn't let us go flying .. now they make us go ". This is one of the worries associated with a general deskilling of the flying workforce ...
In respect of the initial question, if
(a) Vmcg is not a problem
(b) there is adequate spare runway to accommodate the (possibly quite significant) ground run delta
(c) Vr is respected
(d) rotation rate is similar
then, for the same T/W, the speed at screen will be very similar for the V1 and V1- cases.
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If ever there was a case of deliberately putting your foot into a minefield, this one is!!!
As the venerable John_T has put in his 2 cents worth, I'd have to concede that, from a performance perspective, he speaks the truth, BUT............
As John alludes to in point (b) "there is adequate spare runway to accommodate the (possibly quite significant) ground run delta", just how do you know what the runway length requirement would be to accelerate an additional 20 knots with one engine inoperative? There's no AFM data to support this, but by examination of reduced V1s for Wet / Contaminated runways for a few A320 / B737 type aircraft, at least an additional 1000 M (3000 Ft for the Yanks) would be required, AT LEAST!
Even if you do have that additional 1000 M of Runway length available, and, as you're speaking of a continued Takeoff (GO) case, have you considered that in calculating obstacle clearance, the Effective Operational Length (EOL) required to become airborne earlier than the full runway length may be at it's limit well before the runway end? So, you win with respect to the runway length, but hit the obstacle!!! I'll take my chances with the runway, runway over-runs are usually surviveable, obstacle collisions are NOT!
Current operator thinking is to be "GO" minded, I agree with this as a general rule, but methinks that we have taken it a little too far, to the point where it has become an article of religious faith
Regards,
Old Smokey
As the venerable John_T has put in his 2 cents worth, I'd have to concede that, from a performance perspective, he speaks the truth, BUT............
As John alludes to in point (b) "there is adequate spare runway to accommodate the (possibly quite significant) ground run delta", just how do you know what the runway length requirement would be to accelerate an additional 20 knots with one engine inoperative? There's no AFM data to support this, but by examination of reduced V1s for Wet / Contaminated runways for a few A320 / B737 type aircraft, at least an additional 1000 M (3000 Ft for the Yanks) would be required, AT LEAST!
Even if you do have that additional 1000 M of Runway length available, and, as you're speaking of a continued Takeoff (GO) case, have you considered that in calculating obstacle clearance, the Effective Operational Length (EOL) required to become airborne earlier than the full runway length may be at it's limit well before the runway end? So, you win with respect to the runway length, but hit the obstacle!!! I'll take my chances with the runway, runway over-runs are usually surviveable, obstacle collisions are NOT!
Current operator thinking is to be "GO" minded, I agree with this as a general rule, but methinks that we have taken it a little too far, to the point where it has become an article of religious faith
Regards,
Old Smokey
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Artificial V1's have been around for many years. If you continue above Vmcg, then you should maintain directional control through Vr and get airborne, but as Old Smokey suggests, maybe for not too long!
Damned if you do and damned if you don't!
At least make an immediate and aggressive decision, should it ever occur.
Damned if you do and damned if you don't!
At least make an immediate and aggressive decision, should it ever occur.
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I tried to take off with 1 eng out(in sim of course, in Toulouse), ATR-42 500, and I succeded....however more than 2500m and 15 t TOW,dry RWY, no wind...
