PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Rumours & News (https://www.pprune.org/rumours-news-13/)
-   -   Air India B788 descends to 200 ft over water at HKG (https://www.pprune.org/rumours-news/616082-air-india-b788-descends-200-ft-over-water-hkg.html)

ray cosmic 9th Dec 2018 15:39

GLS would solve the issue..

Long Haul 9th Dec 2018 16:39


Originally Posted by ManaAdaSystem (Post 10331053)
That is your view, mine is: That’s why they have an off button for the glideslope.

Actually, the B787 also has a switch to turn off the glideslope. The FCOM recommends using this with unreliable indications. It’s called IAN (integrated approach navigation). You arm approach just like on an ILS, only you descend in GP mode instead of GS mode, and you can’t do an autoland.

Vessbot 9th Dec 2018 16:48

Maybe it's time to match operations to reality (i.e., that a standard approach is on the ILS with the AP, and anything else is a quasi emergency) and protect the GS critical area no matter what the weather is.

So there's a note that legally transfers responsibility... what's the flight crew supposed to do with that info, hand fly the approach? I think that ship has sailed.

777fly 9th Dec 2018 16:59

It’s noteworthy that the incident aircraft was B788. The B787 has a FMC generated approach system called I.A.N. This is in most respects the same as a Vnav approach, except that it generates a (usually) 3 degree approach path out from the runway to the FAF and an inbound course, termed FAC. It is beautifully simple in that normal ILS approach procedures are used, even for a VOR approach, when final approach FMAs would read SPD/FAC/GP.
With known GS fluctuations this crew could have entered the ILS procedure but selected G/S off. This would have generated a hybrid IAN approach in LOC/ GP mode and would have been independent of, and impervious to, G/S fluctuations. Maybe they didn’t understand the system. Further: the B787 has a superb VSD ( vertical situation display) which would have been clearly showing the aircraft flight path directed to a point well short of the runway.

Bengerman 9th Dec 2018 17:42

Did anyone look out of the window?

aterpster 9th Dec 2018 17:42


Originally Posted by Long Haul (Post 10331869)


Actually, the B787 also has a switch to turn off the glideslope. The FCOM recommends using this with unreliable indications. It’s called IAN (integrated approach navigation). You arm approach just like on an ILS, only you descend in GP mode instead of GS mode, and you can’t do an autoland.

That's a nice feature.

ironbutt57 9th Dec 2018 23:04


Originally Posted by Bengerman (Post 10331914)
Did anyone look out of the window?

apparently not

Icarus2001 10th Dec 2018 02:31


that a standard approach is on the ILS with the AP, and anything else is a quasi emergency
I really hope that you are joking.

ACMS 10th Dec 2018 03:06

Whilst conducting a VOR approach to RWY 34 at YMML in their super dooper 787 AI tried to land at YMEN airport in good weather a while ago. Seems they still cannot do any RNAV approaches........

Vessbot 10th Dec 2018 03:06


Originally Posted by Icarus2001 (Post 10332155)
I really hope that you are joking.

About 50/50

Capn Bloggs 10th Dec 2018 12:53


Originally Posted by Aterpster
It's called reading the notes.

If only that comment was in the notes! ;)

Jepp has put the note about the LOC being useable in The Notes section, but not the note/Caution about the GS interference. Not desirable.

aterpster 11th Dec 2018 12:50


Originally Posted by Capn Bloggs (Post 10332497)
If only that comment was in the notes! ;)

Jepp has put the note about the LOC being useable in The Notes section, but not the note/Caution about the GS interference. Not desirable.

Look at Post #57. The note is prominent and in the plan view.

Boeing_Guy 12th Dec 2018 15:29


Originally Posted by Bengerman (Post 10331914)
Did anyone look out of the window?

When I was flying airliners, an instructor saw me focusing too much on the outside and he told me to follow FD down to 50 feet.
This was in Asia !!!!

BleedingOn 12th Dec 2018 18:04


Originally Posted by Bengerman (Post 10331914)
Did anyone look out of the window?

Being a 787 then I would very much hope they were looking out of the window, through the HUD.

vilas 13th Dec 2018 06:40

When crew is informed about GS unreliability they needed to have a plan to mitigate the threat. Close monitoring of GS with ILS DME and when required disengaging the GS and selecting appropriate VS, planning a LOC only approach or switching to visual approach are part of the options. From available evidence it appears the threat was not assessed in it's entirety and suitable threat mitigation was not planned. Surely action based on GPWS cannot be a safe option. The CVR read out should reveal the crew thought process if any. Since the issue is recurring event I hope the airline quickly addresses the issue and circulates the information and procedures to manage the threat.

FlightDetent 13th Dec 2018 13:44

True vilas, and very systematic. Only half of the story though, the less important one. It is not right they did not have a workable plan to a known hazard, what's wrong is how the situation was allowed to unfold.

The A/C left 1700 ft 2 NM before the G/S intercept point and dived with 2700 fpm. Eventually becoming stabilized with -2000 fpm' for 40 seconds until approx 400 ft AGL. Then an adjustment was made reducing to -300 fpm for another 40 seconds, still descending to surface.

Apart from the preparation, assessment and mitigation that śhould have been in place, a completely different toolbox of skills was not present to stop the developing situation. If the report and corrective actions are only limited to what you describe - stage 1 - of what happened, it would be a very sad state of affairs. A missed opportunity as well, let's wait and see.

vilas 14th Dec 2018 14:03


The A/C left 1700 ft 2 NM before the G/S intercept point and dived with 2700 fpm. Eventually becoming stabilized with -2000 fpm' for 40 seconds until approx 400 ft AGL. Then an adjustment was made reducing to -300 fpm for another 40 seconds, still descending to surface
I hadn't seen this. No approach has such high descent segment and that itself is an indicator that something is wrong and immediately it should have been stopped. Shudder to think if GPWS was U/S.

Jet Jockey A4 15th Dec 2018 11:59

LOL... All these excuses, always excuses. No one is flying the aircraft anymore and using their common sense... If I'm flying an aircraft at 1700' AGL and the machine decides on its own to leave that altitude 2.0 nm before the G/S intercept point and starts a 2700 feet per minute descent then it's time for some "real" pilot thinking and action… Like I said before... Click, click... Autopilot "OFF" fly manually!

Too many idiots flying aircrafts these days.

glofish 15th Dec 2018 12:31


Originally Posted by Jet Jockey A4 (Post 10336266)
LOL... All these excuses, always excuses. No one is flying the aircraft anymore and using their common sense... If I'm flying an aircraft at 1700' AGL and the machine decides on its own to leave that altitude 2.0 nm before the G/S intercept point and starts a 2700 feet per minute descent then it's time for some "real" pilot thinking and action… Like I said before... Click, click... Autopilot "OFF" fly manually!

Too many idiots flying aircrafts these days.

I wouldn't call them idiots, they're only inept and incapable.
Idiots, and i am staying politically correct because privately i use more stringent terms, are the regulators giving them a licence and airline managers giving them a seat.

Jet Jockey A4 15th Dec 2018 17:32


Originally Posted by glofish (Post 10336282)
I wouldn't call them idiots, they're only inept and incapable.
Idiots, and i am staying politically correct because privately i use more stringent terms, are the regulators giving them a licence and airline managers giving them a seat.

I'll go along with that!:ok:


All times are GMT. The time now is 03:55.


Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.