Positive Rate?
Joined: Apr 2003
Posts: 578
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From: Sutton
If you have an engine failure on a heavily loaded poor performance type the lag in a VSI can be a problem. Once you are off the ground you have a positive rate....waiting for a significant VSI display of this before retracting gear can result in a very long, very slow and very low fly bys.
Joined: Feb 2005
Aviation Qualifications: ATPL
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From: Correr es mi destino por no llevar papel
One would also add:
4. ASI (Airspeed increasing)
4. ASI (Airspeed increasing)
Joined: May 2000
Posts: 3,204
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From: Seattle
Don't forget the clicks of all the relays and interlocks as the ground sensors do their thing. The VSI may show a transient on rotation before the main gear get off the ground.
I listen for the clicks, THEN confirm with altimeter and VSI (which is usually the last one).
I listen for the clicks, THEN confirm with altimeter and VSI (which is usually the last one).
Joined: Jan 2006
Posts: 2,480
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From: In a far better place
Don't forget the clicks of all the relays and interlocks as the ground sensors do their thing. The VSI may show a transient on rotation before the main gear get off the ground.
I listen for the clicks, THEN confirm with altimeter and VSI (which is usually the last one).
I listen for the clicks, THEN confirm with altimeter and VSI (which is usually the last one).
If the landing gear lever can't be raised after take off, Boeing procedures state the the gear must remain down. Flaps up on schedule. After flaps are up and lights are out, and if the takeoff configuration warning horn remains silent and if the trust levers are beyond the vertical position... landing gear lever override trigger pull... landing gear lever up and off.
Last edited by captjns; 14th September 2006 at 13:38.
Joined: Jun 2002
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From: EGKK
BOAC, Pitch attitude is not an indication of aircraft performance. I welcome you to come flying with me and I will demonstrate the pitch attitudes to which you refer and not only will I be able to do so in level flight, but also with an indicated rate of descent.
I am crediting you with being a Professional Aviator, so it with great discomfort that I ask you to return to Excercise 19 of the PPL syllabus. The attitude/attitude indicator is merely an indication of just that, not aircraft performance.
I am crediting you with being a Professional Aviator, so it with great discomfort that I ask you to return to Excercise 19 of the PPL syllabus. The attitude/attitude indicator is merely an indication of just that, not aircraft performance.
Per Ardua ad Astraeus
Joined: Mar 2000
Posts: 18,575
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From: UK
QAR, I used to teach that, hence my post 'I would add'. Let me put it another way - given that your 3 cues look fine, but the a/c is at that time de-rotating, would you be happy to call 'positive climb'?
Joined: May 2000
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From: Seattle
The only "click" that may be audible in non EFIS type aircraft is the landing gear lever latch solenoid.
Joined: Mar 2000
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From: Arizona USA
The following is a quote from the PanAmerican B707 AFM....
Select the landing gear up after confirming a positive climb is indicated on the pressure altimeter.
True then, on this old design, and true today, on new(er) aircraft.
Is the pressure altimeter the most accurate and reliable instrument for indicating a positive climb is established?
Then, as now....absolutely.
Select the landing gear up after confirming a positive climb is indicated on the pressure altimeter.
True then, on this old design, and true today, on new(er) aircraft.
Is the pressure altimeter the most accurate and reliable instrument for indicating a positive climb is established?
Then, as now....absolutely.
Joined: Sep 2002
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From: La Belle Province
I'd tend to suggest that a pressure sensing device, mounted on or near the nose of an aircraft, while that aircraft is perhaps both rotating and/or moving through ground effect may not be the most reliable indicator of absolute altitude. I've certainly seen the raw pressure data do unusual things during the unstick portion of a takeoff. I would suggest that the radalt has at least as good a chance of being an accurate indicator (with its own caveats regarding terrain profiles and the effect of pitch attitude, of course)
Joined: Mar 2000
Posts: 8,571
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From: Arizona USA
That may well be true, Mad (Flt) Sceintist, however I did leave out one word in the quote presented, which might mitigate your concerns...
"Select the landing gear up after confirming a sustained positive climb is indicated on the pressure altimeter"
"Select the landing gear up after confirming a sustained positive climb is indicated on the pressure altimeter"
Joined: Sep 2002
Posts: 49
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From: Middle East
BOAC,
The aircraft can be, and sometimes MUST be, "de-rotated" (I prefer a "decrease in target pitch attitude"), to maintain a positive rate of climb. For example; if the rotation is to the all engine operative target attitude, and an engine failure occured at the rotation or shortly thereafter, then a positive rate of climb could well result. However as speed started to fall below V2 a decrease in pitch to the engine-out target attitude would be required to maintain airspeed and, ultimately, a postitive rate of climb. In the all engine case, over-rotation may also require a decrease in pitch attitude while still maintaining a positive rate of climb.
Apart from all that, lesson #1 states that POWER + ATTITUDE = PERFORMANCE. QAR ASR would like to demonstrate this to you! In all types rotation is always to the "target attitude" and then performance is checked and attitude adjusted as required by performance. Performance can only be indicated by performance instruments (in this case some combination of IVSI, Altimeter, RA or VSI). Also more than one sustained indication is required, especially in older types where instrument lag and VSI rotation error (rotational forces leading to an indicated rate of descent) may be a factor. Flight manuals, or training manuals, will give this information for the applicable type.
As for "clicks", well it's an interesting theory, but those clicks could be loose objects falling from the galley benches or whatever. Reminds me of a reject at moderate speed when a mobile phone went off during the take off run! The guilty party was in the jump seat and closely related to the skipper!
The aircraft can be, and sometimes MUST be, "de-rotated" (I prefer a "decrease in target pitch attitude"), to maintain a positive rate of climb. For example; if the rotation is to the all engine operative target attitude, and an engine failure occured at the rotation or shortly thereafter, then a positive rate of climb could well result. However as speed started to fall below V2 a decrease in pitch to the engine-out target attitude would be required to maintain airspeed and, ultimately, a postitive rate of climb. In the all engine case, over-rotation may also require a decrease in pitch attitude while still maintaining a positive rate of climb.
Apart from all that, lesson #1 states that POWER + ATTITUDE = PERFORMANCE. QAR ASR would like to demonstrate this to you! In all types rotation is always to the "target attitude" and then performance is checked and attitude adjusted as required by performance. Performance can only be indicated by performance instruments (in this case some combination of IVSI, Altimeter, RA or VSI). Also more than one sustained indication is required, especially in older types where instrument lag and VSI rotation error (rotational forces leading to an indicated rate of descent) may be a factor. Flight manuals, or training manuals, will give this information for the applicable type.
As for "clicks", well it's an interesting theory, but those clicks could be loose objects falling from the galley benches or whatever. Reminds me of a reject at moderate speed when a mobile phone went off during the take off run! The guilty party was in the jump seat and closely related to the skipper!
