Air India B788 descends to 200 ft over water at HKG
Join Date: Nov 2000
Location: UK
Posts: 121
Likes: 0
Received 0 Likes
on
0 Posts
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.
Join Date: Sep 2016
Location: USA
Posts: 803
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Last edited by Vessbot; 9th Dec 2018 at 17:03.
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.
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.
Guest
Join Date: Apr 2009
Location: On the Beach
Posts: 3,336
Likes: 0
Received 0 Likes
on
0 Posts
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.
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........
Originally Posted by Aterpster
It's called reading 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.
Guest
Join Date: Apr 2009
Location: On the Beach
Posts: 3,336
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Jul 2018
Location: Planet Earth
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,404
Likes: 0
Received 0 Likes
on
0 Posts
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.
Last edited by vilas; 13th Dec 2018 at 07:18.
Only half a speed-brake
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.
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.
Join Date: Jun 2007
Location: Wanderlust
Posts: 3,404
Likes: 0
Received 0 Likes
on
0 Posts
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
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.
Too many idiots flying aircrafts these days.
Join Date: Sep 2011
Location: earth
Posts: 1,098
Likes: 0
Received 0 Likes
on
0 Posts
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.
Too many idiots flying aircrafts these days.
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.
