JenCluse
30th Apr 2009, 13:58
Bottom line Acc/Stop check
__________________________
The Oz ATSB Transport Safety Report on the Emirates tail strike at MEL back on the 20th Mar, ( 'Aviation Occurrence Investigation – AO-2009-012, Preliminary' at < http://www.atsb.gov.au/publications/investigation_reports/2009/AAIR/pdf/AO2009012_Prelim.pdf >) has been released.
I have extracted and blown up page 29 of the report (the graphic log of the T/O roll, and extracted a couple of data points.
I hesitatingly responded to the initial discussion thread with a couple of observations re RW16 and it’s winds, and on speed for distance T/O performance ball park checks.
I suggested that, at that time of night, an evening SE breeze usually results in a tailwind on RW16, and the FDR log confirms this. The 12 kt tailwind they experienced in the rotate area should be well know. Work on -5kts average, unless there is a howling southerly blowing.
But what I attempted to put out there was my ‘rough guide to a T/O acceleration acceptability check’ of 80 kt at the 1,500’ (454 m) runway touchdown marking.
And sure enough. Allowing for data blurring, and, as I mentioned earlier these comments, extracted from a 400% blow-up of an extract of the T/O data (page 29) of the .pdf report . . . (rather clear, actually.)
At the 1.500’ marker they were doing approx. 72 kt. (I would have expected 80 kt, *minimum.*)
Hackles would have risen, #1
80 kt was achieved well after the (non-existant) 2,000’ marker disappeared. (Approx 610m down runway.)
Hackles should have risen, #2
(With zero distance gone/to-go information available, even Yaweh/God/Allah would have difficulty judging where He/She/They/It was/were at 80 kt, but the data plots support my premise.)
I mentioned Air Forces’ use of speed by distance calculations.
I still believe that speed Vs distance is the *only* valid performance check, and have argued such with my late employer’s performance engineers at some length, to a deafening chorus of closed minds.
My rule of thumb would have made for an early rejection that night at Tullamarine.
Could you support such an abort before a management review board? Not on the given knowledge. However, with a modicum of knowledge, and a strong Union you could.
Ah. But yes. Reality bites. The AFAP lost. Bugger.
May I suggest you at least add it to your raft of similar rules of thumb, and sundry cross checks? It at least might mean you don’t burn at the other end.
FWIW.
__________________________
The Oz ATSB Transport Safety Report on the Emirates tail strike at MEL back on the 20th Mar, ( 'Aviation Occurrence Investigation – AO-2009-012, Preliminary' at < http://www.atsb.gov.au/publications/investigation_reports/2009/AAIR/pdf/AO2009012_Prelim.pdf >) has been released.
I have extracted and blown up page 29 of the report (the graphic log of the T/O roll, and extracted a couple of data points.
I hesitatingly responded to the initial discussion thread with a couple of observations re RW16 and it’s winds, and on speed for distance T/O performance ball park checks.
I suggested that, at that time of night, an evening SE breeze usually results in a tailwind on RW16, and the FDR log confirms this. The 12 kt tailwind they experienced in the rotate area should be well know. Work on -5kts average, unless there is a howling southerly blowing.
But what I attempted to put out there was my ‘rough guide to a T/O acceleration acceptability check’ of 80 kt at the 1,500’ (454 m) runway touchdown marking.
And sure enough. Allowing for data blurring, and, as I mentioned earlier these comments, extracted from a 400% blow-up of an extract of the T/O data (page 29) of the .pdf report . . . (rather clear, actually.)
At the 1.500’ marker they were doing approx. 72 kt. (I would have expected 80 kt, *minimum.*)
Hackles would have risen, #1
80 kt was achieved well after the (non-existant) 2,000’ marker disappeared. (Approx 610m down runway.)
Hackles should have risen, #2
(With zero distance gone/to-go information available, even Yaweh/God/Allah would have difficulty judging where He/She/They/It was/were at 80 kt, but the data plots support my premise.)
I mentioned Air Forces’ use of speed by distance calculations.
I still believe that speed Vs distance is the *only* valid performance check, and have argued such with my late employer’s performance engineers at some length, to a deafening chorus of closed minds.
My rule of thumb would have made for an early rejection that night at Tullamarine.
Could you support such an abort before a management review board? Not on the given knowledge. However, with a modicum of knowledge, and a strong Union you could.
Ah. But yes. Reality bites. The AFAP lost. Bugger.
May I suggest you at least add it to your raft of similar rules of thumb, and sundry cross checks? It at least might mean you don’t burn at the other end.
FWIW.