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Testing of idle reverse thrust before takeoff. A wise precaution?

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Testing of idle reverse thrust before takeoff. A wise precaution?

Old 23rd Mar 2019, 11:19
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Testing of idle reverse thrust before takeoff. A wise precaution?

https://avherald.com/h?article=4c5b3f3d&opt=0

An A320 lands and reverse thrust fails to operate. There had been no prior warning flags in the cockpit. Maintenance staff had forgotten to remove the reverser lockout pins after servicing. The situation could have been critical if a high speed rejected takeoff occurred at the departure airfield and the crew were unaware the reversers had been locked out.

System caution lights have removed the once good airmanship requirement of the momentary testing of brakes after moving from the tarmac. However, the above incident illustrates that on this occasion a fault in reverser operation did not show up to the cockpit crew until too late

A short test of reverse idle at an appropriate point before takeoff would have revealed this maintenance defect.. Another cue for good airmanship?
.
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Old 23rd Mar 2019, 12:40
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A short test of reverse idle at an appropriate point before takeoff would have revealed this maintenance defect.. Another cue for good airmanship?
.
Not for me thanks. A reverser not working is rarely that big a deal on landing, but messing with reversers before take off just doesn’t give me a good vibe!
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Old 23rd Mar 2019, 13:13
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Originally Posted by A37575 View Post
https://avherald.com/h?article=4c5b3f3d&opt=0

An A320 lands and reverse thrust fails to operate. There had been no prior warning flags in the cockpit.
Which is one reason why PM calls reversers green/amber during rollout.

..........and the crew were unaware the reversers had been locked out.
I think the reverser lockout pins are visible on the sides of the engine nacelle, when fitted?

......... Another cue for good airmanship?
Or checking during the walkaround to see if the lockout pins had been fitted?

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Old 23rd Mar 2019, 13:24
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A reverser not working is rarely that big a deal on landing
But could be a seriously big deal on a high speed rejected take off if runway limited..
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Old 23rd Mar 2019, 13:27
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A thought

The plane is certified to stop safely with the reversers locked out.

Give a thought to how many tasks you want to perform over and above what's in the manuals
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Old 23rd Mar 2019, 14:00
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Originally Posted by A37575 View Post
But could be a seriously big deal on a high speed rejected take off if runway limited..
As lomapaseo has said, even in that case a failure should not be too critical. And how often are we really runway limited on take off? Going full power/ full length.
Iím with the previous poster. Why make things more complicated? KISS. YMMV
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Old 23rd Mar 2019, 14:12
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Originally Posted by A37575 View Post

A short test of reverse idle at an appropriate point before takeoff would have revealed this maintenance defect.. Another cue for good airmanship?
.
Just in case I would also check the spoilers movement, and check the engines are getting up to toga thrust should I need it, and also check the flaps travel down to 3 if I need to come back quickly and also I would close manually the outflow vale and pressurise the plane to check it does pressurise. Anyway short answer to the above : no, it's not, as performance data is there for you to consider a no reverse situation up to a contaminated runway.
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Old 23rd Mar 2019, 14:32
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I agree with most of the posters here: itís not a major issue 99.99% of the time should they not deploy, plus static use of of thrust reversers is not helpful in terms of FOD and/or surging. After all, if youíre going to check they work properly that involves full reverse...
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Old 23rd Mar 2019, 15:53
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Many aircraft require a pre-take-off reverser check as part of the taxi checklist.
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Old 23rd Mar 2019, 16:19
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Originally Posted by josephfeatherweight View Post
Many aircraft require a pre-take-off reverser check as part of the taxi checklist.
Any specifics ?
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Old 23rd Mar 2019, 16:30
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Forty+ years ago on the B707-436 with R-R Conway engines reverse was indeed checked on taxy out. Try that with a JT3D powered aircraft and you will be in a whole world of pain!
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Old 23rd Mar 2019, 16:30
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Originally Posted by A37575 View Post
But could be a seriously big deal on a high speed rejected take off if runway limited..
On dry runways the effect of REV is not taken into account for PERF calculations. The scenario you fear is (all need to apply at the same time)
- wet runway or worse
- ASDA limited take-off
- RTO at V+-10 to V1

The chances are very remote. For what is left, the standard walk around check of REV lock-out pins should cover. No need to envisage new procedures where at least 50% compliance with the present ones would do. Agreed?

-----

although from the report: https://www.atsb.gov.au/media/577576...-064_final.pdf
it is not clear whether the standard pin as seen here https://www.atsb.gov.au/media/577576...-064_final.pdf was visible on the outside of the casing.

Now, the paragraph "AMM specific wording of HMU deactivated ..." of the report is the funny part.
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Old 23rd Mar 2019, 17:04
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Originally Posted by A37575 View Post
https://avherald.com/h?article=4c5b3f3d&opt=0
An A320 lands and reverse thrust fails to operate. There had been no prior warning flags in the cockpit. Maintenance staff had forgotten to remove the reverser lockout pins after servicing. The situation could have been critical if a high speed rejected takeoff occurred at the departure airfield and the crew were unaware the reversers had been locked out.
Highly visible lock out pins should have been caught on even the most cursery walkaround.
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Old 23rd Mar 2019, 17:42
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The HCU is under the pylon on left side underneath the cowling, it isn't visible externally so can't detect incorrect HCU config during walk-around.

There is a streamer-free pin that lives up there and stays with the aircraft. that is what the engineers used to lock out the reversers and forgot to remove.

Very sloppy maintenance. If I'm not mistaken, landing performance is predicated on braking action with nil reverser credit? (I'm not a pilot).
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Old 23rd Mar 2019, 18:15
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Originally Posted by QuarterInchSocket View Post
Very sloppy maintenance. If I'm not mistaken, landing performance is predicated on braking action with nil reverser credit? (I'm not a pilot).
Correct. The only difference is that, in case of landing on a contaminated runway, You need to take it into account from a performance point of view (i.e. add the impact of a no reverser configuration).
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Old 23rd Mar 2019, 18:33
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Thanks sonicbum. I forgot to ask. Would the takeoff run be the same?
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Old 23rd Mar 2019, 18:45
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Just follow SOPs

I agree with the Ďnot a good ideaí crowd.

Also on every Boeing Iíve flown selecting REV on the ground deletes all your Vspeeds from the FMC.

Keep It Simple, just follow manufacturer and company SOPs.

The willingness not to, as alluded to by some of the questions on this forum, do make me worry about my fellow aviators.
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Old 23rd Mar 2019, 18:47
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Originally Posted by atakacs View Post

Any specifics ?
Global Express, Citations, I suspect Gulfstreams too. Never seen in done on modern airliners though

Last edited by AMEX; 23rd Mar 2019 at 18:48. Reason: correction
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Old 23rd Mar 2019, 19:29
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A proper walk around/cockpit preparation goes a long way to prevent stuff like this... Should’ve spotted the reverse lockout pins and all this discussion would be inexistent.

As sonicbum said, might as well check everything every time, just in case.

Reverse is not credited for RTO in dry runways, it is credited for wet or contaminated runways though
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Old 24th Mar 2019, 03:18
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Originally Posted by Meikleour View Post
Forty+ years ago on the B707-436 with R-R Conway engines reverse was indeed checked on taxy out. Try that with a JT3D powered aircraft and you will be in a whole world of pain!

Ok, Iíll bite, why is that ?
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