V2 Climb question
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V2 Climb question
Iam a F/O on a regonal turbo prop and I have a question regarding a climb after departure from one of our ports.
Our company escape procedure states. For runway 18
" at 600 ft turn right onto heading 360 do not retract flap until turn complete intercept the 300 radial climb to MSA"
The airport is surrounded by high terrain to the south and a departure from runway 36 not always avaliable.
My question is should one climb at V2 to the acceleration altitude or climb at best rate or angle ?
Most Captains choose to fly at V2 but there is one in particular that flies it at Vy stating that if you climb at V2 and lose an engine you will lose to much energy and drop below your V2 climb speed this is why he chooses to fly at the faster speed.
My thoughts are you should climb at V2 as this is what the perfomance information is calculated on particularly the turn.
Any thoughts ?
Our company escape procedure states. For runway 18
" at 600 ft turn right onto heading 360 do not retract flap until turn complete intercept the 300 radial climb to MSA"
The airport is surrounded by high terrain to the south and a departure from runway 36 not always avaliable.
My question is should one climb at V2 to the acceleration altitude or climb at best rate or angle ?
Most Captains choose to fly at V2 but there is one in particular that flies it at Vy stating that if you climb at V2 and lose an engine you will lose to much energy and drop below your V2 climb speed this is why he chooses to fly at the faster speed.
My thoughts are you should climb at V2 as this is what the perfomance information is calculated on particularly the turn.
Any thoughts ?
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If it is the escape path then the assumption is that you have already lost an engine. How many engines do you have on this turboprop?
Assuming it is two and you have lost one then V2 would be correct.
Assuming it is two and you have lost one then V2 would be correct.
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Although your post was not absolutely clear at first, I see what your question is. It is my belief that the captain who flies at Vy instead of V2 on a normal departure with no failures to acceleration altitude is CORRECT. Your philosophy is that since engine out is based on V2, you should maintain V2 on every normal take-off until you have reached your normal acceleration altitude, just in case you do have an engine failure, and have to revert to the engine out procedure. His explanation is also logical.
For Eu Ops CS 25/FAR25 aircraft, the AFM climb performance is normally based on V2, thus fly V2.
However, if the turn requires an angle of bank greater than 15 deg, for a lower radius turn, then a higher speed may be specified. If required, this should be in the procedure; also check for any wind limits which might affect the assumed ground track.
If the engine failure occurs at a speed above V2, then maintaining that speed should give a better performance profile, but check the procedure detail and assumptions.
Also check, up to what point the engine failure is assumed after takeoff such that the procedure applies, i.e. after what point do you continue with a normal departure.
IMHO the Captain who flies a speed other than V2 is mistaken in his knowledge of aircraft performance and aerodynamics. Entering a turn at V2, the aircraft would be expected to fly at a lower attitude than for wings-level flight, thus adjust accordingly. If, in error, wings level attitude is maintained in a turn then speed will reduce; do not fly below V2.
Maintain V2 or the speed specified in the procedure.
However, if the turn requires an angle of bank greater than 15 deg, for a lower radius turn, then a higher speed may be specified. If required, this should be in the procedure; also check for any wind limits which might affect the assumed ground track.
If the engine failure occurs at a speed above V2, then maintaining that speed should give a better performance profile, but check the procedure detail and assumptions.
Also check, up to what point the engine failure is assumed after takeoff such that the procedure applies, i.e. after what point do you continue with a normal departure.
IMHO the Captain who flies a speed other than V2 is mistaken in his knowledge of aircraft performance and aerodynamics. Entering a turn at V2, the aircraft would be expected to fly at a lower attitude than for wings-level flight, thus adjust accordingly. If, in error, wings level attitude is maintained in a turn then speed will reduce; do not fly below V2.
Maintain V2 or the speed specified in the procedure.
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Sorry safetypee,
Couldn't disagree more! You follow the aom climbout procedure! Every takeoff has a escape maneuver, whether it be straightout or a turn! You follow the aom climbout profile. Should the engine fail before reaching v2 then you accelerate to v2, should the engine fail at v2 than you maintain v2 should the engine fail above v2 then you pitch up to decelerate to the speed given by the aom( usually anywhere between v2 and v2 +10) any speed above v2 on two engines gives you generally speaking beter climb performance than v2 so you clear the obstacles sooner.
So in answer to the initial poster, the one captain was right as long as the Vy was not above the recommended climbout profile speed you maintain to two engine acceleration height according to the aom.
If memory serves me right, on the fokker 50 you would pitch up to about 10 degrees which would give you about slightly more than v2+ 10, if the engine failed above this speed you would reduce speed to v2+10 if it failed between v2 and v2+10'you would maintain current speed!
Couldn't disagree more! You follow the aom climbout procedure! Every takeoff has a escape maneuver, whether it be straightout or a turn! You follow the aom climbout profile. Should the engine fail before reaching v2 then you accelerate to v2, should the engine fail at v2 than you maintain v2 should the engine fail above v2 then you pitch up to decelerate to the speed given by the aom( usually anywhere between v2 and v2 +10) any speed above v2 on two engines gives you generally speaking beter climb performance than v2 so you clear the obstacles sooner.
So in answer to the initial poster, the one captain was right as long as the Vy was not above the recommended climbout profile speed you maintain to two engine acceleration height according to the aom.
If memory serves me right, on the fokker 50 you would pitch up to about 10 degrees which would give you about slightly more than v2+ 10, if the engine failed above this speed you would reduce speed to v2+10 if it failed between v2 and v2+10'you would maintain current speed!
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I don't consider myself as an expert at performance, but I am in agreement with one of the previous posters, this procedure or escape maneuver is followed if you lose an engine after V1, in which case, V2 would be appropriate until reaching SE ACC altitude.
This maneuver is not to be followed when all engines are operating normally.
This maneuver is not to be followed when all engines are operating normally.
flyburg,
I attempted to be as accurate as I could in my post; I referred to a better performance profile, whereas you discuss better climb performance, which I interpret as instantaneous climb gradient.
The obstacle clearance profiles are based on climb gradient with an engine failing at V1. An engine failure at any time after V1 puts the aircraft in a more advantageous altitude position; but the crew do not know what the value of that is.
I agree with you; if below V2 accelerate to V2 and climb at V2, if above V2, say V2+10, then maintaining that speed should meet all of the initial performance requirements, but specific issues in company published emergency turn procedures should be checked.
With an engine failure above V2+10, the aircraft should similarly have an advantage, but without knowing the speed excess or altitude advantage gained so far, then the crew may wish to fly V2+10 or Vfto. My post might not have clarified these details.
However, harsh or rapid pitch manoeuvring should be avoided in order to achieve a slower speed, (cf DC10 Chicago accident), and in most circumstances a large speed reduction would not be required as such scenarios are more likely after commencing a normal departure route; then the aim is to meet the gradient requirement in that procedure. IIRC one of the normal departures from Lugano had several emergency climb break points, rerouting the normal departure to one of several alternative emergency engine-fail procedures with speed requirements.
I attempted to be as accurate as I could in my post; I referred to a better performance profile, whereas you discuss better climb performance, which I interpret as instantaneous climb gradient.
The obstacle clearance profiles are based on climb gradient with an engine failing at V1. An engine failure at any time after V1 puts the aircraft in a more advantageous altitude position; but the crew do not know what the value of that is.
I agree with you; if below V2 accelerate to V2 and climb at V2, if above V2, say V2+10, then maintaining that speed should meet all of the initial performance requirements, but specific issues in company published emergency turn procedures should be checked.
With an engine failure above V2+10, the aircraft should similarly have an advantage, but without knowing the speed excess or altitude advantage gained so far, then the crew may wish to fly V2+10 or Vfto. My post might not have clarified these details.
However, harsh or rapid pitch manoeuvring should be avoided in order to achieve a slower speed, (cf DC10 Chicago accident), and in most circumstances a large speed reduction would not be required as such scenarios are more likely after commencing a normal departure route; then the aim is to meet the gradient requirement in that procedure. IIRC one of the normal departures from Lugano had several emergency climb break points, rerouting the normal departure to one of several alternative emergency engine-fail procedures with speed requirements.
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The original poster's question is simple. Do you fly at V2 on a normal take-off with 2 engines? Safetypee you say yes or no? If you say no than you agree with the captain who doesnt maintain V2.
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Is the Vy for flaps extended or clean?
What does the TO guidance mode steer to with AEO. Many steer to V2+10 AEO and V2 to V2 +10 OEI.
Do you fly the "escape procedure" when AEO?
What does the TO guidance mode steer to with AEO. Many steer to V2+10 AEO and V2 to V2 +10 OEI.
Do you fly the "escape procedure" when AEO?
ETP's are suppose to be designed so that should you have an engine failure, you'd fly V2 - V2+20 until completion of the ETP and above MSA. Acceleration altitude is secondary when Terrain is a factor, so you only accelerate at the Minimum Flap Retract Altitude once clear of Terrain.
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Could the original poster explain the turn a bit further (degree of curve and bank angle)....and I am curious on the term 'escape procedure', if this is an EO departure, is the track close to the same as the AE departure track, or completely different? (many diverse departures have you climb to 400 and turn) Thanks.
stormyweathers, you may not have interpreted the question in the same way which I have.
The question refers to an escape procedure, which I relate to an emergency procedure with turn (ETP), it is only used with an engine failure (OEI); hence the reference to V2, etc.
If the question is for all engines (AEO) a very unusual procedure, then the speed to be flown should be specified in the procedure. This speed will affect the obstacle clearance achieved, and if it is V2 then either a bank limit or a speed addition to maintain stall margin should also be specified for the turn.
More details required. See FE Hoppy #13 and FlightPathOBN #15
The question refers to an escape procedure, which I relate to an emergency procedure with turn (ETP), it is only used with an engine failure (OEI); hence the reference to V2, etc.
If the question is for all engines (AEO) a very unusual procedure, then the speed to be flown should be specified in the procedure. This speed will affect the obstacle clearance achieved, and if it is V2 then either a bank limit or a speed addition to maintain stall margin should also be specified for the turn.
More details required. See FE Hoppy #13 and FlightPathOBN #15
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As the original poster I should have been more clear, we fly the escape procedure as a matter of course on every departure due to the terrain, (approx 5 miles from the Departure end of the runway) so in my example given the Captains in question are flying it AEO. The inital turn is conducted at 30 AoB AEO, and specifiecs 15 AoB OEI.
Thanks for the replies.
Thanks for the replies.
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You're flying at V2 with 30° bank!
Not sure of the specifics, but I would look at getting the bank angle down, if the same track works with EO works at 15 degree bank angle, why the 30 AE?
It also may help to look at starting the turn at the min of 400, with less bank angle...even 15 EO is a stretch, and a lower turn start would give you some extra room, but there may be other reasons not readily apparent.
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No safetypee. I try never to interpret. The question REFERS to I quote: "...there is one particular captain...stating...if you climb at V2 AND LOSE AN ENGINE...you WILL lose too much energy...and DROP BELOW your V2 speed" Therefore he obviously still has his TWO engines. Now the poster wants to know whether that captain's explanation is valid?
If you're at V2 with all engines, and you suddenly lose an engine,(worst case right engine during a right turn) while in a 30 degree turn, you will lose serious lift. You will have to pitch down to recover the lost speed while decreasing the angle of bank to 15 degrees and regain V2. You will lose height as you pitch down to recover.
While with TWO ENGINES, speed is your friend, not your enemy. Use Vy while you can to increase your height. Also, at what angle of bank would you stall at V2? Assuming the right engine fails during a right turn, you might temporarily exceed the 30degrees that you are already in, before recognizing the failure and recovering and might exceed your stall angle...making things a real mess. I think the captain is right and has thought this through carefully.
If you're at V2 with all engines, and you suddenly lose an engine,(worst case right engine during a right turn) while in a 30 degree turn, you will lose serious lift. You will have to pitch down to recover the lost speed while decreasing the angle of bank to 15 degrees and regain V2. You will lose height as you pitch down to recover.
While with TWO ENGINES, speed is your friend, not your enemy. Use Vy while you can to increase your height. Also, at what angle of bank would you stall at V2? Assuming the right engine fails during a right turn, you might temporarily exceed the 30degrees that you are already in, before recognizing the failure and recovering and might exceed your stall angle...making things a real mess. I think the captain is right and has thought this through carefully.
Last edited by stormyweathers; 11th Aug 2011 at 17:57.