AF777 TOGA after thrust reverser deployment

[TURIN]

Originally Posted by tdracer

I think that part is the key of the statement - "If an engine stays in reverse".
As I noted previously, Boeing reverser design has been changed so that - baring a failure - the reversers won't stay in reverse even after liftoff, they will continue the stow cycle until they are stowed and locked.
.

There's the rub. Barring a failure. I've seen enough reversers fail deployed after landing to know it's not uncommon.

[fab777]

Originally Posted by Disso

Not surprising that such poor airmanship directly against the FCTM is being committed by AF pilots smfh.

Maybe a little bit fast at pointing finger without thinking first... if a pilot, have you ever wonder how you would react if everything happened at the same time, touchdown, immediate and instinctive reverse selection, and got around call from PM/commander? Hey, we even have an example of a US airbus aborting take off for a petty reason (no v speed inserted, nothing that will prevent flying) AFTER LIFT OFF (which is, in my book, against the FCTM) and we don't call out the lack of airmanship of this US airline's pilots, after all.

BTW, which fantastically arimanshipped airline are you flying for? I'm pretty sure I will be able to find a low airmanship blunder by one of your colleague (I have a feeling you are French, by the way you use the verb "commit")

[FlightDetent]

Originally Posted by tdracer

That's fine on paper, but what would you do if, seconds after you selected reverse, a vehicle or another aircraft appeared on the runway? Just go ahead and run into it?

Probably yes, trying to steer clear off it. The A350 in Japan protected the occupants after all. The distance required to liftoff is significant and you'd end up crashing into the obstacle with a higher speed, or worse partially airborne.

My plane stops completely withing 1500' with max effort, but surely won't get climbing with a reverser out and ground spoilers deployed to begin with.

[RichardJones]

Once reverse is deployed on any a/c you are committed.to landing. Period.

[Sailvi767]

I think some of the posts on here fail to account for time to spool a fan engine while the aircraft is moving. The 777 is going to need 8 or more seconds to spool a engine. If the reverser is unlocked even longer. At 100 knots you are traveling almost 170 feet per second. You will need almost 1400 feet of runway before you reach Go Around power. You now need to accelerate to takeoff speed before getting airborne. call it 3000 feet and you might be close to clear a very short obstacle. Again if the reversers are unlocked this distance will be longer. Just a guess but I bet most airliners can stop from 100 knots in 1500 feet or less on a dry runway with maximum braking.

[tdracer]

Originally Posted by Sailvi767

I think some of the posts on here fail to account for time to spool a fan engine while the aircraft is moving. The 777 is going to need 8 or more seconds to spool a engine.

Actually, the regulation says 8 seconds or less from approach idle to go-around. The GE90 does it in about 6 seconds at sea level static (and the idle logic will hold it at approach idle for several seconds after touchdown before allowing decel to min (ground) idle. In addition, although idle needs to be commanded prior to stowing the T/R, the engine itself doesn't have to decel that low before the T/R will stow.

Originally Posted by Sailvi767

Just a guess but I bet most airliners can stop from 100 knots in 1500 feet or less on a dry runway with maximum braking.

Cranbrook occurred in the middle of a snowstorm, and a runway that had an accumulation of snow at the time. They cleared the snowplow, and it would have been a non-event if the reversers used the current design logic.
Again, this would be split second decision by the PF - and their lives (along with the passengers) depend on getting it right... We design for the possibility that they may decide their best chance is to go-around.

[Sailvi767]

Originally Posted by tdracer

Actually, the regulation says 8 seconds or less from approach idle to go-around. The GE90 does it in about 6 seconds at sea level static (and the idle logic will hold it at approach idle for several seconds after touchdown before allowing decel to min (ground) idle. In addition, although idle needs to be commanded prior to stowing the T/R, the engine itself doesn't have to decel that low before the T/R will stow..

If you are down to 100 knots in the example I used you will be at ground idle. Spool time from ground idle is significantly longer. If you are just touching down at 140 knots you will still eat up 1400 or so feet before fully spooled. I was not referring to the snowplow incident in my example. Most pilots don’t realize you can get a jet airborne in about the same distance from a stop as you can from 100 knots if you spool the engines before brake release.
One of the reasons the A330-900 has such poor takeoff performance in a cross wind is the ridiculous amount of runway you eat up with the multistage spooling process.

[tdracer]

I agree, if you're down to 100 knots, then you are probably better off trying to stop - even on a low friction runway.
What I'm talking about is - you touched down and just selected reverse (so still in the 140-150 knot range), and something appears blocking in front blocking the runway. That's when an 'aborted landing' after T/R selection might make sense.

[FlightDetent]

This aeroplane at MLW is 130-135 when "just selected REV". V squared matters.

Also, I like to assume being able to scan the runway 2000' upfront before committing to touchdown in the first place. On a daily basis, 1600' seems to be the legal requirement.

[Fursty Ferret]

That's when an 'aborted landing' after T/R selection might make sense.

Both Boeing and Airbus tell you that there are circumstances in which taking a big risk will mitigate a potentially catastrophic outcome (eg exceeding engine limits to avoid ground contact). It’s very telling that when it comes to thrust reverser deployment they are unequivocal: a full stop landing must be made.

You’re beyond test pilot territory if you continue and a failure to stow is uncommanded engine idle or shutdown at best, hull loss at worst (with secondary casualties on the ground).

[5star]

FCTM, FCOM, QRH are quite clear... A go around, after reversers deployment, should NOT be attempted! So, unless there was an emergency ( eg runway uncursion?) I cannot see what would justify a decision like this one. Just my 2 cts, having flown the Triple for nearly 20 years.

But then again…we know from previous events, they are indeed very very special @ Air France!

Another aknowledgement, why I will never let my family travel onboard AF…

Glad this one ended well! Thanks for sharing btw!

[NoelEvans]

Originally Posted by 5star

...

But then again…we know from previous events, they are indeed very very special @ Air France!

Another aknowledgement, why I will never let my family travel onboard AF…

...

Agreed!

When travelling as pax for work once, I phoned my wife after successfully disembarking with the opening words: "I have just survived a flight in an Airbus flown by Air France pilots..."

A Frenchman that I once worked with pointed out (correctly) that Air France have killed more people than any other airline in Europe.

And here they go-around after selecting reverse thrust...