King Air down at Essendon?
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On the question of Rudder Boost. In the real aircraft in the event of either a flameout/failure or reducing thrust by power lever, the rudder boost only moves the rudder pedal about 50mm. It's more of a "push this one" than any meaningful rudder force in terms of aerodynamic usefulness. Even at zero thrust or autofeathered you still need full rudder deflection and if you are going to hold it there for any more than about 30 seconds, you'll be needing full rudder trim as well.
I have noticed over the years there is a difference in pilot handling and one can tell those you have practiced a V1 cut verses those that havn't almost immediately.. The V1 cut pilot, rotates, applies full rudder, selects gear up, checks power and trims. Fly the body angle restore the heading. Where autofeather has worked normally there's nothing left to do until cleanup altitude which will take a few minutes.
Those pilots who have not trained for a V1 cut, execute the excercise after the gear is up. These pilots tend to hold the rudder force without rudder trim for the whole of the engine failure drill, particularly where the examiner restores thrust immediately after the initial drill is completed.
In my humble opinion, there is no substitute for good simulator training in a good simulator with an instructor that knows his ****.
I have noticed over the years there is a difference in pilot handling and one can tell those you have practiced a V1 cut verses those that havn't almost immediately.. The V1 cut pilot, rotates, applies full rudder, selects gear up, checks power and trims. Fly the body angle restore the heading. Where autofeather has worked normally there's nothing left to do until cleanup altitude which will take a few minutes.
Those pilots who have not trained for a V1 cut, execute the excercise after the gear is up. These pilots tend to hold the rudder force without rudder trim for the whole of the engine failure drill, particularly where the examiner restores thrust immediately after the initial drill is completed.
In my humble opinion, there is no substitute for good simulator training in a good simulator with an instructor that knows his ****.
Yes you're quite right machtuk, Without getting too technicaI, was referring to the case where V1/VR are the same speed. That accelerate stop from VR is not an option as would be the case if operating from a 1000M runway. commonly known or refferred to as claytons 20.7.1b
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it's not mandatory to rotate at that calculated speed.
Depends on whether you want to make the scheduled distance or not ... critical length runway with close-in obstacles might make the plan uncomfortable, perhaps ?
Depends on whether you want to make the scheduled distance or not ... critical length runway with close-in obstacles might make the plan uncomfortable, perhaps ?
Yeah look we're damned if we do and we're damned if we don't. If we crash half the aviation community is going to say, why didn't you stop, the other half is going to say why didn't you fly it away. It comes down to pilot in command decision which should be made as a consequence of good training. Personally, I would'nt like to be rejecting a takeoff from 100kts unless I was taking off from an 1800m plus runway. propsforever, you're all over it spot on.
I should have mentioned if you do VR go, you need to know something about special procedures, flight path and obstacle clearance. It hasn't gone un-noticed that few pilots in this class of aircraft have little to no knowledge about that.
I should have mentioned if you do VR go, you need to know something about special procedures, flight path and obstacle clearance. It hasn't gone un-noticed that few pilots in this class of aircraft have little to no knowledge about that.
Last edited by Xeptu; 4th Oct 2018 at 10:24. Reason: extended
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That's not what is taken into the calculations, Vr is the MINIMUM speed to START the action that results in rotating, you must stay on the rwy till the A/C is under control then rotate. There would be enough Rwy left in all but extreme cases otherwise it wouldn't be a balanced field length. I recently did a LR45 rating & my Sim buddy one day panicked when he had a V1 cut so he just reefed it off the deck & we all died!....I've come back as a shieler this time....lolol
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Yeah look we're damned if we do and we're damned if we don't. If we crash half the aviation community is going to say, why didn't you stop, the other half is going to say why didn't you fly it away. It comes down to pilot in command decision which should be made as a consequence of good training. Personally, I would'nt like to be rejecting a takeoff from 100kts unless I was taking off from an 1800m plus runway. propsforever, you're all over it spot on.
I should have mentioned if you do VR go, you need to know something about special procedures, flight path and obstacle clearance. It hasn't gone un-noticed that few pilots in this class of aircraft have little to no knowledge about that.
I should have mentioned if you do VR go, you need to know something about special procedures, flight path and obstacle clearance. It hasn't gone un-noticed that few pilots in this class of aircraft have little to no knowledge about that.
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That's not what is taken into the calculations, Vr is the MINIMUM speed to START the action that results in rotating, you must stay on the rwy till the A/C is under control then rotate.
Now, that's a tad different to what the design stuff has to say on the matter .. can you cite some authoritative references for your statement ? Alternatively, one could run with the more standard thought that Vr is chosen to achieve V2 for the OEI failure case. If you delay the rotation, you will exceed V2 and the numbers game gets a bit messy. (Irrelevant for the FAR 23 case).
Now, that's a tad different to what the design stuff has to say on the matter .. can you cite some authoritative references for your statement ? Alternatively, one could run with the more standard thought that Vr is chosen to achieve V2 for the OEI failure case. If you delay the rotation, you will exceed V2 and the numbers game gets a bit messy. (Irrelevant for the FAR 23 case).
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That's not what is taken into the calculations, Vr is the MINIMUM speed to START the action that results in rotating, you must stay on the rwy till the A/C is under control then rotate.
Now, that's a tad different to what the design stuff has to say on the matter .. can you cite some authoritative references for your statement ? Alternatively, one could run with the more standard thought that Vr is chosen to achieve V2 for the OEI failure case. If you delay the rotation, you will exceed V2 and the numbers game gets a bit messy. (Irrelevant for the FAR 23 case).
Now, that's a tad different to what the design stuff has to say on the matter .. can you cite some authoritative references for your statement ? Alternatively, one could run with the more standard thought that Vr is chosen to achieve V2 for the OEI failure case. If you delay the rotation, you will exceed V2 and the numbers game gets a bit messy. (Irrelevant for the FAR 23 case).
Last edited by machtuk; 5th Oct 2018 at 10:36.
Flying faster than V2 if you are already faster than V2 is not the same as delaying rotation beyond Vr. On a limiting runway, delaying Vr would compromise the screen height.
I'd also suggest that if you are 15º off heading, remaining on the runway any longer than necessary would not be wise.
I'd also suggest that if you are 15º off heading, remaining on the runway any longer than necessary would not be wise.
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You seem to miss the point. ALL the numbers are minimums, V1 is the only exact number because it's known as a decision speed, clear cut, Vr & V2 do NOT have to be adhered to as long as they are not acted upon or flown LESS than calculated.
If you're talking about the FAR25 numbers, then I'm with JT and Aerocat - delaying Vr invalidates your BFL numbers.
Flying faster than V2 if you are already faster than V2 is not the same as delaying rotation beyond Vr. On a limiting runway, delaying Vr would compromise the screen height.
I'd also suggest that if you are 15º off heading, remaining on the runway any longer than necessary would not be wise.
I'd also suggest that if you are 15º off heading, remaining on the runway any longer than necessary would not be wise.
My experience of deliberately holding an aircraft on the runway beyond Vr is that nosewheel steering is not made easier by excessive forward control column pressure and everything starts to feel wrong.
Vr = rotate = time to go. Runway behind you isn’t going to be a whole lot of help anytime soon.
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My experience of deliberately holding an aircraft on the runway beyond Vr is that nosewheel steering is not made easier by excessive forward control column pressure and everything starts to feel wrong.
My instructor was ex-Fokker 100s and his practice was to hold the column forward as takeoff power was applied and leave it there until Vr, although on my type we didn’t use V speeds. I learned quickly that neutral to slight forward pressure was a lot safer. And that once you’re actually flying, you’re better off to leave the ground behind positively.
My only multi FW time was about ten minutes the left seat of F-27 VH-TFK in the cruise as a seventeen year old, only pax on board and not being operated by its owner TAA, but I have to say I'm somewhat disappointed when I see V1 referred to as a "decision speed". The FAA defines it as,
EASA use the same definition. Tis an action speed, which follows the decision made X seconds prior. CASA, unfortunately define V1 as a "decision speed", so the community can be forgiven its misunderstanding. JT may wish to contribute as to the use of the "decision speed" term, which is widely used in educational material.
Further,
V1 means the maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes) to stop the airplane within the accelerate-stop distance. V1 also means the minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.
Further,
§25.107 Takeoff speeds.
(a) V1 must be established in relation to VEF as follows:
(1) VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant, but may not be less than VMCG determined under §25.149(e). (2) V1, in terms of calibrated airspeed, is selected by the applicant; however, V1 may not be less than VEF plus the speed gained with critical engine inoperative during the time interval between the instant at which the critical engine is failed, and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot's initiation of the first action (e.g., applying brakes, reducing thrust, deploying speed brakes) to stop the airplane during accelerate-stop tests.(b) V2MIN, in terms of calibrated airspeed, may not be less than—
(1) 1.13 VSR for—
(i) Two-engine and three-engine turbopropeller and reciprocating engine powered airplanes; and(ii) Turbojet powered airplanes without provisions for obtaining a significant reduction in the one-engine-inoperative power-on stall speed;(2) 1.08 VSR for—
(i) Turbopropeller and reciprocating engine powered airplanes with more than three engines; and (ii) Turbojet powered airplanes with provisions for obtaining a significant reduction in the one-engine-inoperative power-on stall speed; and(3) 1.10 times VMC established under §25.149. (c) V2, in terms of calibrated airspeed, must be selected by the applicant to provide at least the gradient of climb required by §25.121(b) but may not be less than—(1) V2MIN; (2) VR plus the speed increment attained (in accordance with §25.111(c)(2)) before reaching a height of 35 feet above the takeoff surface; and(3) A speed that provides the maneuvering capability specified in §25.143(h).(d) VMU is the calibrated airspeed at and above which the airplane can safely lift off the ground, and con- tinue the takeoff. VMU speeds must be selected by the applicant throughout the range of thrust-to-weight ratios to be certificated. These speeds may be established from free air data if these data are verified by ground takeoff tests.(e) VR, in terms of calibrated airspeed, must be selected in accordance with the conditions of paragraphs (e)(1) through (4) of this section
1) VR may not be less than—
(i) V1;
(ii) 105 percent of VMC;
(iii) The speed (determined in accordance with §25.111(c)(2)) that allows reaching V2 before reaching a height of 35 feet above the takeoff surface; or
(iv) A speed that, if the airplane is rotated at its maximum practicable rate, will result in a VLOF of not less than —
(A) 110 percent of VMU in the all-engines-operating condition, and 105 percent of VMU determined at the thrust-to-weight ratio corresponding to the one-engine-inoperative condition; or
(B) If the VMU attitude is limited by the geometry of the airplane (i.e., tail contact with the runway), 108 percent of VMU in the all-engines-operating condition, and 104 percent of VMU determined at the thrust-to-weight ratio corresponding to the one-engine-inoperative condition.(2) For any given set of conditions (such as weight, configuration, and temperature), a single value of VR, obtained in accordance with this paragraph, must be used to show compliance with both the one-engine-inoperative and the all-engines-operating takeoff provisions.(3) It must be shown that the one-engine-inoperative takeoff distance, using a rotation speed of 5 knots less than VR established in accordance with paragraphs (e)(1) and (2) of this section, does not exceed the corresponding one-engine-inoperative takeoff distance using the established VR. The takeoff distances must be determined in accordance with §25.113(a)(1).(4) Reasonably expected variations in service from the established takeoff procedures for the operation of the airplane (such as over-rotation of the airplane and out-of-trim conditions) may not result in unsafe flight characteristics or in marked increases in the scheduled takeoff distances established in accordance with §25.113(a).(f) VLOF is the calibrated airspeed at which the airplane first becomes airborne.
(g) VFTO, in terms of calibrated airspeed, must be selected by the applicant to provide at least the gradient of climb required by §25.121(c), but may not be less than—
(1) 1.18 VSR; and
(2) A speed that provides the maneuvering capability specified in §25.143(h).
(h) In determining the takeoff speeds V1, VR, and V2 for flight in icing conditions, the values of VMCG, VMC, and VMU determined for non-icing conditions may be used.
(a) V1 must be established in relation to VEF as follows:
(1) VEF is the calibrated airspeed at which the critical engine is assumed to fail. VEF must be selected by the applicant, but may not be less than VMCG determined under §25.149(e). (2) V1, in terms of calibrated airspeed, is selected by the applicant; however, V1 may not be less than VEF plus the speed gained with critical engine inoperative during the time interval between the instant at which the critical engine is failed, and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot's initiation of the first action (e.g., applying brakes, reducing thrust, deploying speed brakes) to stop the airplane during accelerate-stop tests.(b) V2MIN, in terms of calibrated airspeed, may not be less than—
(1) 1.13 VSR for—
(i) Two-engine and three-engine turbopropeller and reciprocating engine powered airplanes; and(ii) Turbojet powered airplanes without provisions for obtaining a significant reduction in the one-engine-inoperative power-on stall speed;(2) 1.08 VSR for—
(i) Turbopropeller and reciprocating engine powered airplanes with more than three engines; and (ii) Turbojet powered airplanes with provisions for obtaining a significant reduction in the one-engine-inoperative power-on stall speed; and(3) 1.10 times VMC established under §25.149. (c) V2, in terms of calibrated airspeed, must be selected by the applicant to provide at least the gradient of climb required by §25.121(b) but may not be less than—(1) V2MIN; (2) VR plus the speed increment attained (in accordance with §25.111(c)(2)) before reaching a height of 35 feet above the takeoff surface; and(3) A speed that provides the maneuvering capability specified in §25.143(h).(d) VMU is the calibrated airspeed at and above which the airplane can safely lift off the ground, and con- tinue the takeoff. VMU speeds must be selected by the applicant throughout the range of thrust-to-weight ratios to be certificated. These speeds may be established from free air data if these data are verified by ground takeoff tests.(e) VR, in terms of calibrated airspeed, must be selected in accordance with the conditions of paragraphs (e)(1) through (4) of this section
1) VR may not be less than—(i) V1;
(ii) 105 percent of VMC;
(iii) The speed (determined in accordance with §25.111(c)(2)) that allows reaching V2 before reaching a height of 35 feet above the takeoff surface; or
(iv) A speed that, if the airplane is rotated at its maximum practicable rate, will result in a VLOF of not less than —
(A) 110 percent of VMU in the all-engines-operating condition, and 105 percent of VMU determined at the thrust-to-weight ratio corresponding to the one-engine-inoperative condition; or
(B) If the VMU attitude is limited by the geometry of the airplane (i.e., tail contact with the runway), 108 percent of VMU in the all-engines-operating condition, and 104 percent of VMU determined at the thrust-to-weight ratio corresponding to the one-engine-inoperative condition.(2) For any given set of conditions (such as weight, configuration, and temperature), a single value of VR, obtained in accordance with this paragraph, must be used to show compliance with both the one-engine-inoperative and the all-engines-operating takeoff provisions.(3) It must be shown that the one-engine-inoperative takeoff distance, using a rotation speed of 5 knots less than VR established in accordance with paragraphs (e)(1) and (2) of this section, does not exceed the corresponding one-engine-inoperative takeoff distance using the established VR. The takeoff distances must be determined in accordance with §25.113(a)(1).(4) Reasonably expected variations in service from the established takeoff procedures for the operation of the airplane (such as over-rotation of the airplane and out-of-trim conditions) may not result in unsafe flight characteristics or in marked increases in the scheduled takeoff distances established in accordance with §25.113(a).(f) VLOF is the calibrated airspeed at which the airplane first becomes airborne.
(g) VFTO, in terms of calibrated airspeed, must be selected by the applicant to provide at least the gradient of climb required by §25.121(c), but may not be less than—
(1) 1.18 VSR; and
(2) A speed that provides the maneuvering capability specified in §25.143(h).
(h) In determining the takeoff speeds V1, VR, and V2 for flight in icing conditions, the values of VMCG, VMC, and VMU determined for non-icing conditions may be used.
Last edited by megan; 6th Oct 2018 at 01:16.
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You seem to miss the point.
I don't think so. Your thoughts are at variance with the certification philosophies upon which the performance numbers are built. Indeed, I would dearly love to have a beer or three with your instructors to discuss their views on the subject .. their reported position is a bit of a worry, methinks.
there is no law to state you must be at V2 but usually is V2 + 10/20 in order to achieve the required climb gradient.
I'm afraid it appears that it might be you who is missing the point and I have to wonder if your earlier training may have been a bit deficient ?
For line operations with FAR 25 Types, V2 is based on the OEI case and, unless there be a very good reason to do otherwise, it should be the OEI target for a failure near V1 - for faster than V2 failures, the better climb performance overspeed means that one prefers to hold the margin above V2, generally to a maximum of around V2+20.
If you are AEO (as is the usual case), the preferred technique is to rotate at the AFM (OEI) rate to the Type AEO pitch attitude and hold the resulting speed .. which, generally, is a bit in excess of V2. There is no "required gradient" AEO for the takeoff analysis although the presumption is that the aircraft will be operated in a manner which will keep the AEO flight path above the OEI AFM flight path.
define V1 as a "decision speed"
The design rule book has changed over the years. Hence it is essential to check the TCDS for Type to check on the certification basis (ie which design rules applied to the Type) before one starts looking up the design standards - generally, it is necessary to look at superseded revisions - easy for the FARs via the FAA website.
The V1 concept is no different and it has changed from the earlier "decision" speed idea to the far more practical present Industry approach which can be paraphrased .. "if you haven't already started stopping by V1, then you keep going". Clearly, there may be occasions where the Commander needs to apply his/her prerogative and stop but such situations are in the extreme minority.
The F27 is an extreme case. The original design was to the old design standards. Not all that long after the aircraft came onto the market, it was recertificated to the ICAO PAMC for performance. That report became the basis for modern design standards. Recently I acquired copies (courtesy of zzuf and OG) and, at some stage, will get around to scanning them so that folk who are interested in the design standards history might be able to read a copy. The document is not easy to find .. I have kept my eyes open for one for many years without success until the two good PPRuNe folk mentioned gave me their personal copies.
I don't think so. Your thoughts are at variance with the certification philosophies upon which the performance numbers are built. Indeed, I would dearly love to have a beer or three with your instructors to discuss their views on the subject .. their reported position is a bit of a worry, methinks.
there is no law to state you must be at V2 but usually is V2 + 10/20 in order to achieve the required climb gradient.
I'm afraid it appears that it might be you who is missing the point and I have to wonder if your earlier training may have been a bit deficient ?
For line operations with FAR 25 Types, V2 is based on the OEI case and, unless there be a very good reason to do otherwise, it should be the OEI target for a failure near V1 - for faster than V2 failures, the better climb performance overspeed means that one prefers to hold the margin above V2, generally to a maximum of around V2+20.
If you are AEO (as is the usual case), the preferred technique is to rotate at the AFM (OEI) rate to the Type AEO pitch attitude and hold the resulting speed .. which, generally, is a bit in excess of V2. There is no "required gradient" AEO for the takeoff analysis although the presumption is that the aircraft will be operated in a manner which will keep the AEO flight path above the OEI AFM flight path.
define V1 as a "decision speed"
The design rule book has changed over the years. Hence it is essential to check the TCDS for Type to check on the certification basis (ie which design rules applied to the Type) before one starts looking up the design standards - generally, it is necessary to look at superseded revisions - easy for the FARs via the FAA website.
The V1 concept is no different and it has changed from the earlier "decision" speed idea to the far more practical present Industry approach which can be paraphrased .. "if you haven't already started stopping by V1, then you keep going". Clearly, there may be occasions where the Commander needs to apply his/her prerogative and stop but such situations are in the extreme minority.
The F27 is an extreme case. The original design was to the old design standards. Not all that long after the aircraft came onto the market, it was recertificated to the ICAO PAMC for performance. That report became the basis for modern design standards. Recently I acquired copies (courtesy of zzuf and OG) and, at some stage, will get around to scanning them so that folk who are interested in the design standards history might be able to read a copy. The document is not easy to find .. I have kept my eyes open for one for many years without success until the two good PPRuNe folk mentioned gave me their personal copies.
You seem to miss the point. ALL the numbers are minimums, V1 is the only exact number because it's known as a decision speed, clear cut, Vr & V2 do NOT have to be adhered to as long as they are not acted upon or flown LESS than calculated. If perf allows a healthy climb greater than minimum V2 (you can remain at the current speed if an engine failure occurred above the min V2 speed during initial climb out) then there is no law to state you must be at V2 but usually is V2 + 10/20 in order to achieve the required climb gradient. Anyway I've always been shown during all my type endo's that stay on the Rwy till the A/C is tracking straight even if this means going beyond the MINIMIN Vr speed, its worked for all the 20.7.1B A/C I have been involved with. An Eg when NOT to rotate at Vr if V1 & Vr are the same. You have an engine failure just as you get to V1 (& you go) & the A/C heads bush momentarily (due the startle factor) say off Rwy Hdg by 15 degs towards the grass, are you going to rotate as soon as you heard Vr from the PNF if they are both the same numbers? No bloody way!
There is no specific margin for delaying the rotate, to do so will compromise the TODR/TODA for the actual engine failure case. What time you have is dependent on the relationship of ASDR and TODR.
There is a widespread training position that ensuring the aircraft is stable prior to rotating is acceptable, and that becomes best practice. While that is great when there is spare TODA remaining in front, there is no legal requirement for that to always be the case. Good practice? probably but with a major warning, that any time delaying rotate potentially compromises the go case. In rough terms, in an absolute limiting Go case, with a failure at Vef, and a go decision, that 35' screen height is around 3 seconds of interval, so probably needs to be used wisely. If a wet condition has resulted in a V1 reduction and a commensurate screen height reduction to 15', that is about 2 seconds of play time before you may be catching stuff in the gear. Note if you use the V1 wet reductions that while that is permitted in 25.113, it doesn't rate a mention in 25.115 so it is an open question whether your second segment calculations actually incorporate wet margins. On any given day, you may have enough spare runway (probably will have) in order to be stable for the rotate, but that is not an absolute given. Getting airborne out of control may be a great definition of excitement, but it is not the expected outcome from a trained pilot applying a correction in a timely manner following failure. The good news is that if there is a limited split between V1 and Vr, then logically, the stop case would have additional distance required, (ASDA) and that ensures that there should be some margin in the time to commence rotate. If there is a large split between V1 and Vr, then the issue should not arise, the failure occurs with a fair time to ensure the flightpath is under control. 4 Engine aircraft will have the most limiting conditions in the go case, but then the V1 will also usually have a large split from Vr. The 2 engine aircraft looks great on 2, so the 115% margin is not the limiting case, it is the engine out case, and that may look great until it happens. The 2 engine aircraft will also usually have a lower split in V1 and Vr compared to the 3 or 4 engine case, unless policy is to use a minimum V1 for all performance which can be elected by the operator.
Practically, in a simulator few failures are given at exactly Vef, as the outcome is uncertain, the crew may respond with a go or a stop, and the result could easily be a failure of the check ride. In real planes, training risk management would usually preclude operating anywhere near a limit condition for an practice power loss, and again it won't occur at Vef, the results have too much chance of an adverse outcome. Playing with a Part 25 aircraft with practice engine failures is not an ideal situation, but it still happens. [A while ago, I had a twin jet type check where the DPE slapped the thrust lever back to idle at V1 on a short runway, as we did our initial departure towards the airport that was long enough to do V1 cuts with some margin. Flicking the thrust lever back resulted in the lever going to cuttoff, and the ensuing single engine climb out over a major downtown area was rather quiet in the cockpit. At a safe height, and cleaned up, we got the restart part of the type out of the way. 12 months later, another DPE managed to get dead along with another 2 pilots doing same sort of thing in another corporate jet this time getting a TR deployment, The engine shutting down DPE also managed to become an ex DPE when the wing on the aircraft in a test decided to part company from the rest of the plane in level unaccelerated flight. R.I.P.].
Bottom line is any delay of rotate results in some level of compromise of the takeoff flight path, you as the pilot are paid the big (or small) bucks to make wise decisions on what you see on the day. Whatever you do, you need to achieve the screen height at the end of the TODA, to achieve terrain clearance. Good news is that in the real world most engine failures don't occur at Vef. A failure in the rotate will often give a wild ride, particularly if there was a strong x wind. A failure at low speed in low vis is always interesting as well.
Last edited by fdr; 6th Oct 2018 at 03:02.
Many thanks JT, much obliged. Demonstrates the danger when not everyone is on the same page, need to say V1 (old) versus V1 (new). It might be pointed out that with respect to the KA the FAR 25 is to the new rules.
https://flightsafety.org/fsd/fsd_oct98.pdf
https://flightsafety.org/fsd/fsd_oct98.pdf
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The 2 engine aircraft will also usually have a lower split in V1 and Vr compared to the 3 or 4 engine case
Our performance engineers worked out we could take off from Runway 29 in the 737-200 at max structural and a 10 knot tailwind, Flaps One with a VR around 160 knots. V1 was 23 knots less. Basically the low V1 permitted plenty of room for an abort allowing for the increased ground speed because of the 10 knots TW. The long runway and the 23 knots spread between V1 and VR gave us more than enough to spare accelerating through that 23 knots on one engine. It also gave the pilot lots of time to play with the rudder to maintain the centreline in the GO case albeit slow acceleration on one engine.
We would maintain the localiser reciprocal track during climb out to avoid straying towards a 758 ft high hill situated about half a mile to one side of the localiser track. Personally, in terms of decision making at a critical time during takeoff, I would prefer to have a substantial split between V1 and VR rather than V1=VR or similar tight difference. Any IRE that scrubs a pilot during simulator training having failed an engine two or three knots below V1 and the pilot elects to continue, needs to study the history of accidents caused by a high speed reject close to V1. They do not always go to plan and the result has the potential to be deadly; especially where the over-run area is minimal as in ending in water. Some Pacific atolls for example.
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With an true FAR25 Aircraft like the 737 that might be true.
With a KA200 there is a Problem. Acceleration on one Engine is a bit Asthmatic, so a big split between V1 and VR affects balanced field length, big time..
With the KA250, wich is not a lot more than a 200GT with full Raisbeck Mods, the manufacturer was able to present reasonable BFL Distances, because they could Play with the V-Speeds.
Raisbeck mods lower Vmc, wich was the limiting factor with King Airs.
With a KA200 there is a Problem. Acceleration on one Engine is a bit Asthmatic, so a big split between V1 and VR affects balanced field length, big time..
With the KA250, wich is not a lot more than a 200GT with full Raisbeck Mods, the manufacturer was able to present reasonable BFL Distances, because they could Play with the V-Speeds.
Raisbeck mods lower Vmc, wich was the limiting factor with King Airs.
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Our performance engineers worked out we could take off from Runway 29 in the 737-200 at max structural and a 10 knot tailwind, Flaps One with a VR around 160 knots. V1 was 23 knots less.