c100driver,
In fact, that is close, but no chocolate frog.
The numbers derived from the tables that Boeing and Airbus produce will always ( I have never been able to see anybody demonstrate otherwise) produce a landing field length longer than the raw test flight figure factored by 1.67.
I think I said words to the effect that the landing filed length cannot be less than the statutory length, raw factored by 1.67.
Indeed, some of the recommendations that will be in the forthcoming FAA NPRM will turn some of these recommendations into statutory requirements, and in the case of wet/contaminated runway, looks like they will be greater than the raw figure factored by 1.92
As I alluded to, in a previous post, the "new" approach is very much like (but more conservative than) the BCARs of the 1960s/70s.
Here is the relevant CASA CAO 20.7.1b
11 Landing distance required 11.1 For subparagraph 5.1 (a), the landing distance for a jet-engined aeroplane is:
(a) for an aeroplane engaged in regular public transport operations when landing on a dry runway, or in charter operations when landing on a dry or wet runway — 1.67 times the distance required to bring the aeroplane to a stop on a dry runway; or
(b) for an aeroplane engaged in regular public transport operations when landing on a wet runway:
(i) 1.92 times the distance required to bring the aeroplane to a stop on a dry runway; or
(ii) the distance set out in the flight manual or operations manual for operations conducted on wet runways.
11.1.1 For the purposes of subparagraph 5.1 (a), the landing distance required in relation to a propeller driven aeroplane that is engaged in regular public transport, or charter, operations is:
(a) for a landing at a destination aerodrome:
(i) when the runway is dry — a distance equal to 1.43 times the distance required to bring the aeroplane to a stop; or
(ii) when the runway is wet — a distance equal to 1.67 times the distance required to bring the aeroplane to a stop; and
(b) for a landing at an alternate aerodrome — 1.43 times the distance required to bring the aeroplane to a stop.
11.1.2 Subject to paragraph 11.2, the landing distance required under paragraph 11.1 or 11.1.1 must be determined using information set out in the flight manual.
11.2 For a landing on a contaminated runway, the landing distance required is:
(a) subject to paragraph 11.3, the distance set out in the flight manual or the operations manual for operations conducted on contaminated runways; or
(b) the distance approved by CASA for operations conducted on runways covered by slush, snow or a depth of water.
11.3 For subparagraph 4.1 (d) and paragraph 5.1, an aeroplane engaged in private, or aerial work, operations must be operated so that compliance with the landing requirements is demonstrated using data set out in:
(a) the flight manual; or
(b) the manufacturer’s data manual; or
(c) the approved foreign flight manual.
Note The data contained in some manufacturers’ data manuals is unfactored and makes no allowance for degraded aircraft performance.
11.5 This subsection does not apply in the case of an emergency.
Critical to the reading of the above is the status of the information currently presented. It is a very legalistic approach in Australia, and the differences between certified, acceptable and advisory information is absolutely critical in determining legal compliance. All AFM "data" has to be "accepted" (in reality, approved) by CASA for use under an FCOM, it makes for some very interesting "discussions".
Tootle pip!!