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Old 12th Aug 2002, 15:42   #1 (permalink)
 
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crosswind limits on B-737

According to FCOM limitation chapter, max. Demonstrated crosswind landing limit is 35kts. Itís not limiting, Max. calculated crosswind limit dry surface (as per training manual) is 40 kts. On runways 148ft wide. My question is, ď Is there any formula or ratio to calculate crosswind limits if you are landing on runways less than 148ft wide?Ē
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Old 14th Aug 2002, 05:12   #2 (permalink)

 
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Question

Huh?
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Old 15th Aug 2002, 12:34   #3 (permalink)
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Don't think so, AUW. The rule I use is that the xwind limit is inversely proportional to the thickness of my 'yellow streak' on the day, if that is any help.
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Old 17th Aug 2002, 08:52   #4 (permalink)
 
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Gheeer!!
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Old 20th Aug 2002, 19:35   #5 (permalink)
 
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Dont think so.
The crosswind limits are the "demonstrated" values- so unless they make a narrower runway at Boeing Field.....
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Old 21st Aug 2002, 03:10   #6 (permalink)
 
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Not all crosswind components are demonstrated, some can be derived mathematically, and not all crosswind values are limitations, some are advisory. (Hence the caveat in the 737 limitations)

Part 25.237 "For landplanes and amphibians, a 90-degree cross component of wind velocity, demonstrated to be safe for takeoff and landing, must be established for dry runways and must be at least 20 kts or .2Vso whichever is greater, except that it need not exceed 25 knots."

Last edited by '%MAC'; 21st Aug 2002 at 03:23.
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Old 21st Aug 2002, 03:38   #7 (permalink)
 
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I understand that the there is an approved 737-700 AFM Appendix for operations on runways with widths less than 45 meters, but not less than 30 meters. This appendix contains additional cg limits, a Vmcg speed based on allowing only a 20 foot centerline deviation to retain equivalent safety margins, maximum crosswind limits, visibility, and MMEL considerations.

So you could always ask your airline to buy the appendix!

Mearse.
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Old 21st Aug 2002, 03:56   #8 (permalink)
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Australia, so far as I know, is the only country to have implemented an ICAO thought to address the deficiencies in the geometry based runway width limits which most countries use.

As part of the internal requirements in Australia, if an operator seeks to run the aircraft on narrower than "standard" runways the aircraft has to demonstrate its ability under critical conditions to be able to do so with a high degree of probability of not coming adrift .....

B737 was done for TN/AN some years ago for 100 ft/30 m runways (and would be the basis for the appendix to which Mearse refers) .. Citation for 18 m (which was sold to Cessna and formed the basis for the current Citation narrow runway appendix) .. the Diesel 9 was started, but not finished, for 100 ft/30 m (operator really couldn't see the commercial value in putting itself out to provide the aircraft to suit weather etc .. )

... some interesting pix ... those who were involved learnt all about the problems of putting LOOOONG lenses on videos ...

There were a few other aircraft done .. but I can't bring the individual types to mind .....

The main concerns were associated with the crosswind versus Vmcg problem which Mutt and I regularly air in these forums in a vain effort to get people interested in thinking about odd corners of the envelope in which they might periodically find themselves .... and in which they might get bitten badly on occasion .. whilst thinking that all is well ...

Those of us who were involved in some of these test programs came away quite converted believers ..... if you believe that runway width is NOT important for low speed schedule takeoffs .. then you are a sitting duck for a BIG surprise one of these days ...
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