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Origin of "Scheduled" Performance

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Origin of "Scheduled" Performance

Old 30th Nov 2007, 12:35
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Origin of "Scheduled" Performance

Granted it's not the most technical question that's ever hit this forum but I was wondering where the term "scheduled" performance originates. I know the area of performance that it relates to , but we talk of "scheduled" speeds and "scheduled" distances etc. in the Flight Manual, and, to me it seems an unusual term to use.
Can anybody help?
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Old 30th Nov 2007, 22:29
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An interesting question and one I'd never considered.

Perhaps it developed historically. In the beginning, one either got out of the field .. or didn't, as the case may be. Although one sees elementary performance data in the post war period, this hit and miss technique largely continued up until the ICAO PAMC (provisional acceptable means for compliance) relating to performance came onto the scene around the time of the F27's introduction. I can recall tales from Centaurus along the lines that he used to have some concern with military VIP flying in the pre-jet days where it was left largely up to the commander, somehow, to get it right ... Even now, DC3s and the like have only the most rudimentary performance data (unless things have changed since I last played with a DC3).

The PAMC revolution then developed into the normal extensive certification performance data we have become used to over recent decades.

So far as the term "scheduled" is concerned, I suggest that the Industry arrived at that term to reflect the notion that the weight (mass) aspects of the conduct of operations were constrained by predetermined calculations. These provided predicted maximum weight data for which operations would reasonably be likely to meet the relevant design and operating standards .. hence the idea of scheduling in a manner similar to generating a timetable or other source of predictive reference data.
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Old 1st Dec 2007, 21:10
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Many thanks John.

I think I've seen "scheduled" substituted by "regulated" performance in some discussions. This, as you've suggested, would imply a set of conditions which, if met, have been shown by some regulatory or certification authority to provide the required level of probability of a safe operation, be it a take-off, landing or whatever.

I'm fairly new to the field of aircraft performance and this was one of those innocent "why's that then?" questions that didn't seem to have an answer that I could find written down.

Thanks again

WUT
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Old 1st Dec 2007, 21:37
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"Regulated" (as in RTOW/RTOM) has been the usual term since I were but a young lad and is more the British term, I suspect - "scheduled" is somewhat later and is likely to have originated in the US (?) .. or a least so it appears by my observation. I suggest "regulated" has a similar derivation based on predicted performance and compliance with a set of regulations.

... that didn't seem to have an answer that I could find written down

oh, brother .... get used to that little problem in this game. My first introduction was with one of the Oz majors at the time when I was an undergrad .. I was fortunate to be mentored for a vacation program by one of Oz's most experienced airline performance chaps and my interest developed from there.

If you have an interest in performance, there are a few engineering undergrad level aerodynamics/flight mechanics texts around which you would find useful. If you can get hold of the Boeing Performance Engineers Manual (used for their customer performance course) that is probably the single best text on the subject when it comes to airline-style performance work .. and only about 3-4 inches thick ..

Another source of excellent basic data is in the course notes for the various test pilot schools. The AGARD Flight Test Manual and ESDU Data Sheets, etc., hold a wealth of useful information both for the student and practitioner.
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