first takeoff segment
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first takeoff segment
Hi all,
i'm a bit confused about the first takeoff segment .. some sources say it's screen height (35 ft) to gear up, others say it's from lift off to gear up ..
anyone knows which one is the most correct one (and why)? my guess is from screen height to gear up, as takeoff distance ends at screen height
thanx!!
Jan
i'm a bit confused about the first takeoff segment .. some sources say it's screen height (35 ft) to gear up, others say it's from lift off to gear up ..
anyone knows which one is the most correct one (and why)? my guess is from screen height to gear up, as takeoff distance ends at screen height
thanx!!
Jan
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Post #3 of this thread is probably what you're looking for - as JT suggests, ignore my answer in post 2 as it's not actually speaking the same 'language' as you are asking....
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Plain and simple... first segment commences at lift off and ends when the landing gear is retacted.
Sorry, but no.
First segment is that bit of the gear retraction sequence which extends past the 35ft screen. As such, there may, or may not, be a first segment .. depending on whether the gear is not, or is, respectively, up by the time the aircraft gets to the screen height.
Sorry, but no.
First segment is that bit of the gear retraction sequence which extends past the 35ft screen. As such, there may, or may not, be a first segment .. depending on whether the gear is not, or is, respectively, up by the time the aircraft gets to the screen height.
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Don't have my copy of cs-25 right now and can't be bothered to download it again but, I remember reading something about half the distance from lift off to the screan height being the start and gear up being the end. Also as the great JT said, if the gear is up before 35' you are straight into second segment requirements.
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I sensed the time of year is upon us to get back into the TO perf threads, I love it the cycle of pprune, comencing with V1 then to the screen at V2 or V3 finally past the screen through the flight path, it will turn later into ...then ED's and turning off the path or NOT... cruise performance fuel burn....windshear and finally The Landing
The Seasoning
rhov
The Seasoning
rhov
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.. a few points to ponder ..
(a) wet runway modifies the basic consideration but the principle is still the same
(b) half the distance from lift off to the screan height being the start and gear up being the end. Mixed thoughts here, I'm afraid ... "half the distance" comes into the TORR where half of the total air distance from liftoff to screen has to be over the runway (if you are looking at an older Brit certification, the half may become a third .. but that takes me back a ways ..). The requirement is to reduce the risk of the aircraft's still being on the ground (.. and in the dirt) when clearway is used for the calculations ...
(c) Don't have my copy of cs-25 right now . One always needs to be very wary of reading the current document ... always the need is to establish the certification basis for a given aircraft .. and then read the version of the document which was relevant to the particular certification
(d) me thinks you have more to worry about than the second segment. Fair comment. One needs to keep in mind that the AFM sums are a bit artificial, although based on sensible engineering validated by flight test. More importantly, the normal takeoff is AEO and the gear up sequence is going to be completed much higher. However, for a WAT-limited OEI takeoff, the aircraft may still be quite close to the bitumen when the gear retraction sequence has finished .... which is why ops engineers who fly probably are more interested in first segment considerations than our brother and sister engineers who don't .. witness many of the threads involving Old Smokey, Mutt, etc. which get involved in first segment matters ...
(e) I sensed the time of year is upon us to get back into the TO perf threads. ... which is why those of us with greyer beards are only too happy to nurture the cycle for the benefit of the newer folk who may not have read the similar story previously .. at the end of the day, we should all have a similar goal ... "number of successful landings = number of successful takeoffs" etc.
(a) wet runway modifies the basic consideration but the principle is still the same
(b) half the distance from lift off to the screan height being the start and gear up being the end. Mixed thoughts here, I'm afraid ... "half the distance" comes into the TORR where half of the total air distance from liftoff to screen has to be over the runway (if you are looking at an older Brit certification, the half may become a third .. but that takes me back a ways ..). The requirement is to reduce the risk of the aircraft's still being on the ground (.. and in the dirt) when clearway is used for the calculations ...
(c) Don't have my copy of cs-25 right now . One always needs to be very wary of reading the current document ... always the need is to establish the certification basis for a given aircraft .. and then read the version of the document which was relevant to the particular certification
(d) me thinks you have more to worry about than the second segment. Fair comment. One needs to keep in mind that the AFM sums are a bit artificial, although based on sensible engineering validated by flight test. More importantly, the normal takeoff is AEO and the gear up sequence is going to be completed much higher. However, for a WAT-limited OEI takeoff, the aircraft may still be quite close to the bitumen when the gear retraction sequence has finished .... which is why ops engineers who fly probably are more interested in first segment considerations than our brother and sister engineers who don't .. witness many of the threads involving Old Smokey, Mutt, etc. which get involved in first segment matters ...
(e) I sensed the time of year is upon us to get back into the TO perf threads. ... which is why those of us with greyer beards are only too happy to nurture the cycle for the benefit of the newer folk who may not have read the similar story previously .. at the end of the day, we should all have a similar goal ... "number of successful landings = number of successful takeoffs" etc.
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John_Tullamarine, I really do enjoy the 'change of season' everytime I'm either reminded of something old or learn something new, no two perf threads are worded the same alway a new perspectiv new issues new debates. I think the Seasoning is what makes the Techlog
I look forward to wahts on the horizon for this year...
I think its the winter that makes pilots talk about these things
Happy Takeoffs and Landings
rhov
I look forward to wahts on the horizon for this year...
I think its the winter that makes pilots talk about these things
Happy Takeoffs and Landings
rhov
