Reverse Thrust

[flyandbefree]

I flew 4 sectors on BA in July. BOS-LHR (744) LHR-ATH (757) ATH-LHR (757) and LHR-BOS (744). All 4 landings were done without the use of reverse thrust. I am aware of most of the reasons why one would elect not to use reverse thrust during the roll-out, I was just wondering if there is a specific BA directive/procedure recommending that use of reverse power be avoided. The landing in ATH was in 37C weather so I thought it was hard on the brakes. I am just a curious piston twin driver.

[Cornish Jack]

f&bf
Reverse idle plus autobrake is usually enough to provide adequate stopping distance AND it IMPROVES brake wear..... brakes stay on constant application rather than cycling on/off. Used to be SOP with Birdseed and Sir RB's 400s.

[LEM]

The above is true with carbon brakes only, with steel ones better to brake as least as possible.

A few years ago Qantas one overrun at Bangkok, also because it was company policy to avoid the use of reverse above idle, to impose a greater stress on the brakes thus save them.
The crew was so used to avoid a good handful reverse that they forgot to use it even when the overrun was imminent (!).

Anyway the problem is not cycling the brakes - an average pilot is well capable of braking manually with constant pressure - but is a matter of temperature: carbon brakes like hot temps and live longer.

Another point to consider is that nowadays many airports prohibit use of reverse above idle unless for safety reasons, due to noise.
Many pilots in certain countries still don't comply with that, and they immediately show where they come from...

[flyandbefree]

Thank you both for your answer

[Menen]

Lem. I have read many times that carbon brakes "like" to be used hard and become more efficient the hotter they become.

Am a trifle mystified about this theory (or fact). Could you explain in clear and concise terms (I am a pilot with doubtful grasp of engineering theory - and I am serious about that, unfortunately) why this is so? Thanks in advance.

[LEM]

Good question, Menen, but unfortunately you asked the wrong person.
I know that carbon brakes last longer if used intesively, but I don't know the exact chemical or molecular reason for that.

I'll start a new topic for that, hopefully we'll be enlightened by some scientists... :D

[used2flyboeing]

If you excuse the pun - carbon brake engineering is very much a "black" art - much of the design is based on Emperical evidence - IE they test the hell out of everything - they formulate & reformulate brake compositions - the 737NG had a Main Landing Gear oscillation that was fixed by reformulating brake materials - the point is - I dont think anybody really know why these things work the way they do - not even the engineers ..

[LEM]

That's what I think too...