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#1
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aircraft approach category quandary
I know the aim para 5.4.7 says that aircraft approach categories are
based on 1.3 times the stall speed in the landing config at max certificated gross landing weight (comes from far 97.3 (b). However I know I have read somewhere, perhaps the aim or a far, something along the lines that where the manufacturer has provided data to allow the pilot to determined the approach speed based on weight, that this can then be used to determine which category the aircraft falls in. Does anyone know of where I would have read something along these lines? Stan |
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#3
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"Ron Rosenfeld" wrote in message =
... On Sat, 18 Dec 2004 17:49:42 GMT, wrote: =20 I know the aim para 5.4.7 says that aircraft approach categories are based on 1.3 times the stall speed in the landing config at max certificated gross landing weight (comes from far 97.3 (b). However I know I have read somewhere, perhaps the aim or a far, something along the lines that where the manufacturer has provided data to allow the pilot to determined the approach speed based on weight, that this can then be used to determine which category the aircraft falls in. Does anyone know of where I would have read something along these lines? Stan =20 Perhaps: =20 14 CFR 97.3 =20 (b) Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VS0 at = the maximum certificated landing weight. VREF, VS0, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry. = The categories are as follows: ... =20 --ron Stan: Continuing beyond what Ron quoted, here's more... "If it is necessary to maneuver at speeds in excess of the upper limit of a speed range for a category, the minimums for the next higher category should be used." I don't know why it says "should". I'd expect it to say "must". Anyway, that applies to me. I like to approach with several extra = knots, which bumps me into category B. I think your question was related to the calculation of Vref for the specific landing weight and conditions, as is done when operating heavier, usually turbine-powered, aircraft. |
#4
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In article ,
John R. Copeland wrote: (b) Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VS0 at the Continuing beyond what Ron quoted, here's more... "If it is necessary to maneuver at speeds in excess of the upper limit of a speed range for a category, the minimums for the next higher category should be used." I never understood why they bothered to specify a "book" speed for approach category when the real rule is that it's based on the speed that you fly during the approach. -- Ben Jackson http://www.ben.com/ |
#5
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"Ben Jackson" wrote in message =
news:YL5xd.284746$R05.189455@attbi_s53... =20 I never understood why they bothered to specify a "book" speed for approach category when the real rule is that it's based on the speed that you fly during the approach. =20 --=20 Ben Jackson The reason is based in aerodynamics. 1.3 Vs0 is an acceptable approximation to the point of maximum lift/drag ratio of fixed-wing airfoils on typical small = general-aviation aircraft. That makes it a reasonable target for threshold-crossing speed. |
#6
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In article ,
John R. Copeland wrote: The reason is based in aerodynamics. 1.3 Vs0 is an acceptable approximation to the point of maximum lift/drag ratio of fixed-wing airfoils on typical small general-aviation aircraft. That makes it a reasonable target for threshold-crossing speed. Sure, but the rule doesn't need a number, much less a formula. The rule is effectively "approach class is based on the speed you fly the approach". -- Ben Jackson http://www.ben.com/ |
#7
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I don't know why it says "should". I'd expect it to say "must".
Because wherever you got that isn't a regulatory document. Your source must be either the Pilot/Controller Glossary or the Instrument Flying Handbook. Ron quoted the regulation. |
#8
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#9
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Thanks Ron. My old aim/far does not have the same wording. this is
exactly what I was looking for. Since on most jets, Vref is specified by the manufacturer based on weight, then at near minimum flight weight, vref may be 118 kts, cat B. But at some higher weight, vref may be 125 kts, cat C. Hence this ** regulation ** allows that the aircraft category be determined based on present weight, and not maximum certified weight. And so the quandary is, why would the aim para 5.4.7 be saying that category is based on speed at ** max certified landing weight ** ? Ron Rosenfeld wrote: On Sat, 18 Dec 2004 17:49:42 GMT, wrote: I know the aim para 5.4.7 says that aircraft approach categories are based on 1.3 times the stall speed in the landing config at max certificated gross landing weight (comes from far 97.3 (b). 14 CFR 97.3 (b) Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF is not specified, 1.3 VS0 at the maximum certificated landing weight. VREF, VS0, and the maximum certificated landing weight are those values as established for the aircraft by the certification authority of the country of registry. --ron |
#10
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On Sun, 19 Dec 2004 15:57:55 GMT, wrote:
why would the aim para 5.4.7 be saying that category is based on speed at ** max certified landing weight ** Probably your AIM is old, also: http://www.faa.gov/ATpubs/AIM/Chap5/aim0504.html#5-4-7 5-4-7. Instrument Approach Procedures a. Aircraft approach category means a grouping of aircraft based on a speed of VREF, if specified, or if VREF not specified, 1.3 VSO at the maximum certificated landing weight. ... --ron |
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