Idle reverse = No reverse QRH???
Thread Starter
Joined: Apr 2012
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From: In Space
Idle reverse = No reverse QRH???
Hi guys and girls,
During a flight with a trainer we was discussing Brake cooling.
I suggested, being late at night, using idle reverse (first detent).
The trainer suggested that I look at the brake cooling schedule no reverse detent.
Reason behind it, Idle reverse is the same as idle, so therefore there is no reverse thrust.
I havent heard of this before, but I see the logic, as there are no numbers for idle reverse, using no reverse would be the worst case.
What do you guys think?
During a flight with a trainer we was discussing Brake cooling.
I suggested, being late at night, using idle reverse (first detent).
The trainer suggested that I look at the brake cooling schedule no reverse detent.
Reason behind it, Idle reverse is the same as idle, so therefore there is no reverse thrust.
I havent heard of this before, but I see the logic, as there are no numbers for idle reverse, using no reverse would be the worst case.
What do you guys think?
Joined: May 2013
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From: London
I too refer to the brake cooling schedule no reverse when planning an idle reverse landing. It is certainly often the case, that some guys don't realise how close the caution zone the schedule could be after landing.
Joined: Jun 2001
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From: Boldly going where no split infinitive has gone before..
No, they are different. Idle reverse cancels the residual thrust that still exists at forward idle, and leads to lower brake temperatures.
HOWEVER, as with all things, you get what you pay for. Our QRH used to only have tables for full reverse and no reverse, until we wanted to encourage idle-reverse landings.
A fat cheque to Mr Boeing and the next revision included an idle reverse table.
In the absence of such a table, using no-reverse would be the conservative option.
HOWEVER, as with all things, you get what you pay for. Our QRH used to only have tables for full reverse and no reverse, until we wanted to encourage idle-reverse landings.
A fat cheque to Mr Boeing and the next revision included an idle reverse table.
In the absence of such a table, using no-reverse would be the conservative option.
Last edited by Wizofoz; 7th June 2013 at 16:13.
Joined: Aug 2007
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From: Spain
Reverse Idle
Having watched the green bits at the end of the runway getting closer asked the crew politely why they hadn't selected reverse power. Next flight discussion of whether idle reverse or power reverse during landing briefing.
Joined: Jun 2001
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From: Boldly going where no split infinitive has gone before..
Well, Full Reverse is only going to make a difference to landing roll if you are using max brake energy- otherwise it just allows LESS braking which keeps temperatures down- with carbon brakes it doesn't actually reduce brake wear.
Joined: Sep 2008
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From: 41S174E
Having watched the green bits at the end of the runway getting closer asked the crew politely why they hadn't selected reverse power.
I think it's most likely that Wiz is correct and if they had followed your line of thinking the auto brake system would have simply scheduled less brake when the reverse came in in order to achieve the same deceleration rate. If they were braking manually then more brake pressure would have done the trick unless they were at max manual braking like Wiz said, if they were.....my goodness that must have been exciting!
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From: Europe
Well, Full Reverse is only going to make a difference to landing roll if you are using max brake energy- otherwise it just allows LESS braking which keeps temperatures down- with carbon brakes it doesn't actually reduce brake wear.
Joined: Jun 2001
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From: Boldly going where no split infinitive has gone before..
Actually, no it isn't.
If maximum manual braking will stop the aircraft in the required distance, all reverse thrust will do is lessen that requirement and keep the brakes cooler.
The only time reverse thrust will decrease the available landing roll is when it is used in addition to the maximum amount of wheel braking available.
Clearly, in cases where wheel braking is less effective due to runway conditions, this will be more relevant.
If maximum manual braking will stop the aircraft in the required distance, all reverse thrust will do is lessen that requirement and keep the brakes cooler.
The only time reverse thrust will decrease the available landing roll is when it is used in addition to the maximum amount of wheel braking available.
Clearly, in cases where wheel braking is less effective due to runway conditions, this will be more relevant.
Last edited by Wizofoz; 9th June 2013 at 17:11.
Joined: Dec 2002
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From: UK
Following on from Wizofoz #10, and with more potential for confusion; see slide 29 onwards for a graphical explanation – Airbus.
Pay careful attention to the applicable runway conditions – dry / wet / snow, the differences between manual and autobrake, and that only when you have a higher deceleration is the landing distance shorter.
And something similar from – Boeing.
Pay careful attention to the applicable runway conditions – dry / wet / snow, the differences between manual and autobrake, and that only when you have a higher deceleration is the landing distance shorter.
And something similar from – Boeing.
