747classic,
A well turned phrase, "Reading from the same sheet of music", it sums it up quite well, but the resultant tunes should sound very similar. I used an example where the Australian authorities required deeper interpretation of Flight Manual / Performance Manual data for compliance with the rules there. Before the disappearance of both, Ansett and TAA / Australian Airlines operated identical aircraft over several decades, but the company produced Operations Manuals looked very different.
The bottom line in "Company Derived Data" is that, for acceptance by the relevant authority, it must be shown to be DERIVED from AFM / Performance Manual data. Development of this data is prohibited, and referral will have to be made back to the manufacturer if new data outside the scope of existing data is required (as opposed to that within the scope of existing data). The various authoritys have rules for proving of these data. This will include such things as making available for their assessment computer programmes used for RTOW calculation.
If directly derived from AFM / Performance Manual data, there should be no legal problems following an incident / accident so long as the data is demonstrably in line with AFM, or more conservative. That is, after all, what operating crews do each day, operate in accordance with, or more conservatively than the AFM.
A fairly simple example of data 'derived' from the AFM / Performance Manual. One aircraft I had the task to interpret for the Company Operations Manual had no Engine Inop Ceiling / Drift-Down data available in the AFM. The AFM / Performance Manual DID have a very good table of engine inop gradients for a very comprehensive range of Weights, Pressure Heights, and Temperatures, as well as good data for Referred Fuel Flow at MCT. A table of engine inoperative ceilings was obtained by extracting where, for a particular weight and temperature, gradient was zero. Integration of a series of Gradients, Speed, Fuel Flow (and thus decrementing weight) enabled calculation of the Drift-Down locus, and a table of Time / Fuel / Distance for drift-down to operational ceiling. A quite simple task for a novice performance engineer, but a nightmare in the cockpit if the information was quickly needed. All data emanated from the AFM and Performance Manual, without any 'development'.
To suggest sub-contractors, it will first be necessary to know on which country's register the proposed operation will be. Some sub-contractors (including some very well known ones) have difficulty in acceptance in certain countries, or the sub-contractor is unwilling to take work in a particular country.
Last edited by Old Smokey; 5th August 2004 at 14:55.