Aeroplane performance requirements

[King Red]

Can anyone help.

Am doing a bit of reading up on aeroplane performance and am coming across alot of the legal performance requirements pertaining to various phases of flight which we all should know, but maybe like myself don't (for now).

My question is, why a 3,3% climb gradient after take off. Who decided on 3,3%. Why should an aircraft land within 70% of the landing distance available.

Are these figures and percentages just a thumb suck or has serious research gone into making these law.

If anyone can help with some answers as to WHY it would be highly appreciated. Just makes it easier to explain it to the next chap.

Any source references would be great.

Thanks

[Genghis the Engineer]

I don't know the answer, but much of this content of FARs and JARs came from work done in the 10 years after WW2 by NACA (which later became NASA).

I'd suggest trawling the NACA reports server (link in the sticky at the top of tech log), almost certainly the answer is in there somewhere.

Just hope you have ADSL !

G

[OverRun]

King Red - the good book is P J Swatton 'Aircraft Performance Theory for Pilots". Its about 25 quid from Amazon UK.

I got mine as a Christmas present to myself. Very good read. Makes one appreciate the performance chaps.

The 70% LDA is turboprop only, and (p 268) provides for the difference between 'maximum braking' and 'normal braking plus normal operational variabilities'.