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Idle reverse = No reverse QRH???

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Idle reverse = No reverse QRH???

Old 7th Jun 2013, 14:57
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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?
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Old 7th Jun 2013, 15:15
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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.
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Old 7th Jun 2013, 16:11
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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.

Last edited by Wizofoz; 7th Jun 2013 at 16:13.
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Old 7th Jun 2013, 18:02
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reverse debate

Agree with wiz, no reverse = residual thrust, idle reverse = no residual thrust. Also, the added bonus that in FDTM no reverse = snotogramme from FDTM facilitator.
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Old 7th Jun 2013, 18:11
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Thanks for answering.
I had the same thinking as you Wiz, and didnt agree that idle and reverse idle are the same.

A lot of EU aerodromes ask for Idle reverse for noise abatement.
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Old 7th Jun 2013, 23:16
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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.
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Old 8th Jun 2013, 05:04
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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.
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Old 8th Jun 2013, 06:56
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Having watched the green bits at the end of the runway getting closer asked the crew politely why they hadn't selected reverse power.
What type of aircraft was it?
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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Old 9th Jun 2013, 16:34
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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.
This is assuming autobrake is used, and that braking action is not a problem...
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Old 9th Jun 2013, 17:10
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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.

Last edited by Wizofoz; 9th Jun 2013 at 17:11.
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Old 9th Jun 2013, 17:28
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Reverse idle on the 737 (200) is defined as 1.1 EPR, to ensure that there is no residual fwd thrust.
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Old 9th Jun 2013, 17:40
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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.
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