PPRuNe Forums - View Single Post - B737-800 Flap speeds
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Old 23rd May 2007, 09:36
  #17 (permalink)  
john_tullamarine
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Interesting thread so far .. two comments I would echo ..

(a) ... If you really need to get down then you can use the very simple formula of 1000feet/nm. plus two miles to spool up/stabilise at 500agl. .... I have seen it done quite safely from 7500 with 10.5 track miles to run.

Personally don't like full flap but approach flap with a bit of speed on works to give around 1/1. I routinely used this to effect DRW-CNS in westerlies .. approaching overhead the upwind end at around 10000 and then a dirty idle descent down to end downwind .. spin up ... landing flap and a normal base and final. Worked a treat and the pax didn't have their teeth rattled out of their heads with turbulence generated gyrations ..

(b) the limitations address the basic structural requirements and a presumed operational scenario for fatigue calculations. He who routinely pushes the gear and flap limit speeds goes outside the normal sort of fatigue presumptions and will experience a significant increase in routine maintenance costs for gear doors etc., and flap hardware. Probably not an accident concern if the routine maintenance is kept up to the mark as the hangar boys (most likely) will find the usual cracking long before things depart from the base structure. But it's a very silly operational and commercial practice. In the occasional emergency situation where you MUST get down .. the considerations are quite different. However, for routine operational use, the sums just don't add up.
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