AF777 TOGA after thrust reverser deployment

[Eutychus]

[mods please move if this is in the wrong place]

A YouTube channel I follow has just reposted this video this video of an AF 777 landing at Mumbai, starting to deploy thrust reversers and then doing a go-around. That sounds like a risky call to this SLF*. Isn't one committed to landing after thrust reverser deployment?

*My main qualification here is having flown *out* of Mumbai once right at the back of an A340 with AF's now-defunct low-cost long-haul operation Joon...

[tdracer]

[mods please move if this is in the wrong place]

A YouTube channel I follow has just reposted this video this video (https://www.youtube.com/watch?v=xsjIXRBwJpQ&t=0s) of an AF 777 landing at Mumbai, starting to deploy thrust reversers and then doing a go-around. That sounds like a risky call to this SLF*. Isn't one committed to landing after thrust reverser deployment?

*My main qualification here is having flown *out* of Mumbai once right at the back of an A340 with AF's now-defunct low-cost long-haul operation Joon...
As I recall, the AFM says something to the effect of 'Go-Around not recommended after thrust reverser deployment'.
That being said, it does happen, and all current Boeing products are designed to accommodate it (outgrowth of the 737-200 crash at Cranbrook - go-around after a snowplow appeared out of the snow after T/R deployment - one T/R didn't complete the stow cycle and lock prior to liftoff and aero forces caused it to deploy again.).

[Disso]

Very relevant Mentour Pilot episode covering this, ironically, just posted named "A FREAK Coincidence?! Tap Air Portugal flight 754". (I can't post links yet)

FWIW, he is extremely adamant throughout the video in concluding that once reversers are deployed, you are 1000% COMMITTED to completing the landing and NOT going around.

[Propellerhead]

Once reverse is selected a full stop landing must be made. As you allude to, the air Portugal close call is why, where one stayed in reverse.

[tdracer]

Once reverse is selected a full stop landing must be made. As you allude to, the air Portugal close call is why, where one stayed in reverse.

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?

[Dct_Mopas]

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?

….or try a go-around. Thrust reversers stow, then build up to TOGA thrust from idle once again, slowly get airborne and clip the obstacle at high speed.

If reverse has been selected you stay on the runway and stop. If the obstacle is so close that you can’t stop in time with maximum braking then you most certainly can’t miss it by trying to get airborne again.

[tdracer]

….or try a go-around. Thrust reversers stow, then build up to TOGA thrust from idle once again, slowly get airborne and clip the obstacle at high speed.

If reverse has been selected you stay on the runway and stop. If the obstacle is so close that you can’t stop in time with maximum braking then you most certainly can’t miss it by trying to get airborne again.
Cranbrook took off in time to miss the snow plow - had the reverser stayed stowed (which, as I noted earlier, has been corrected on Boeing aircraft), it would have been a non-event. If you're going well north of 100knots, it takes a long time to stop vs. taking off again.

Granted, not something that any sane person would plan, but with faced with a certain collision at speed, or getting airborne again, you need to make a rapid decision and then just pray it's the right one. The aircraft design shouldn't be the limiting factor.

[Capn Bloggs]

If reverse has been selected you stay on the runway and stop.
Or, take it on to the grass. Touchdown at 130ish, full braking, max reverse will take you quickly to towards 100, a runway excursion at 100, with all the gear down and full reverse won't seriously hurt anybody. You don't have to "just run into something", in a car or aeroplane.

If you're going well north of 100knots, it takes a long time to stop vs. taking off again.
You'd be surprised. Reverser stowing, spooling up, then finally commencing acceleration back to ~140 will take you longer than a max effort stop from 100kt.

717 FCOM:
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/632x87/717_rev_thrust_warning_069f1d5286b07cf03fe8e5efa23a763fd2f82 b0a.jpg
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[rog747]

If I was sitting in that seat and saw that happen then my bottom hole would be tweaking ever so.....
I heard the note of the engines drop, and then there was seemingly a lag in spool up,
I wasn't too happy LOL.

Glad they flew out of it.

[Propellerhead]

Of course a Commander is authorised to deviate from rules and procedures in an emergency in order to ensure the safety of the aircraft. I don’t believe this was the case with the Air France. To deviate from a Boeing warning in bold type would have to be pretty extreme. Boeing have the risk assessment in the cold light of day.

[mnttech]

717 FCOM:
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/632x87/717_rev_thrust_warning_069f1d5286b07cf03fe8e5efa23a763fd2f82 b0a.jpg

717 or 777? Just because it is in one airframe does not mean it is in another due to the design of the reversers. Some older aircraft used bleed air if I remember correct.
That said, the spool up time I would think would be one issue, let alone if one reverser had an issue.
Are 777 reversers hydraulic on all engine variants ?

[Capn Bloggs]

That is indeed the 717. I don't have a current FCOM for the 777, but an early version I have says essentially the same thing, but not in a Warning box.

[Beakor]

B787 Flight Crew Training Manual 6.21:

“WARNING: After reverse thrust is initiated, a full stop landing must be made. If an engine stays in reverse, safe flight is not possible.”

[tdracer]

Are 777 reversers hydraulic on all engine variants ?

Yes. Not true on many other models though (CF6-80C2 on the 767 and 747-400 are pneumatic for example. while the PW4000 is hydraulic).

[ploughman67]

B787 Flight Crew Training Manual 6.21:

“WARNING: After reverse thrust is initiated, a full stop landing must be made. If an engine stays in reverse, safe flight is not possible.”


Identical wording in the B777 FCTM

[Disso]

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

[Check Airman]

Has there been any attempt to determine WHY this was done, or are we sending them to prison without a trial?

I’m sure everyone’s CAA has a paragraph similar to this:

§121.557 Emergencies: Domestic and flag operations.(a) In an emergency situation that requires immediate decision and action the pilot in command may take any action that he considers necessary under the circumstances. In such a case he may deviate from prescribed operations procedures and methods, weather minimums, and this chapter, to the extent required in the interests of safety.

[tdracer]

If an engine stays in reverse, safe flight is not possible.”

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.
That wasn't the case with Cranbrook - where as soon as air/ground went 'air', all power was removed from the reverser and it was unable to complete the stow cycle.

[Eutychus]

Has there been any attempt to determine WHY this was done, or are we sending them to prison without a trial?

I guess part of my question in starting this thread is whether an event like this does or should trigger any debrief, incident reporting procedure, crew debrief, etc. Either before and after video of the incident goes on YouTube.

(One comment on the video asks whether the captain might not have taken back control from the FO, belatedly, to initiate the go-around).

[FullWings]

It would be interesting to know what the reason was, as it would have to be a seriously good one to reject the landing after reverser deployment. As AF is an EASA operation, they should have done a IFLD assessment, which would have given a stopping margin and gates for a safe touchdown and rollout. Thinking about the sequence of events: flare and thrust to idle, touchdown, reverser deployment, reverser stowing, thrust to GA, accelerate to Vref then rotate, the amount of runway used between touchdown and the wheels leaving the runway again would be substantially more than a normal rejected landing, due to the reversers going in and out, presumably while braking was ongoing.

I’m fairly certain that FOQA would trigger an investigation for this incident, but it would likely be an internal one, unless it was deemed serious enough to pass to the regulator, and even then it may never make it into the public domain.

[TURIN]

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]

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]

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]

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.
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]

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. :ok:

[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]

...

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...