Air India B788 descends to 200 ft over water at HKG
On 20 October 2018, an Air India Boeing 787-8 aircraft, registration VT-ANE, flight number AI314 descended below the glideslope on approach to HKG. Crew went around but came within 200 feet of the water:
https://aviation-safety.net/wikibase/wiki.php?id=219044 (Incidentally the same a/c as the one involved in the incident at ARN recently https://www.pprune.org/rumours-news/...-building.html) |
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"possible glide path fluctuation"...possibly this affected things?
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Ground prox warning alerted the crew...nothing from ATC?
The ac descended rapidly to 200' AGL? Dive to intercept at 2.6nm? |
Glide path fluctuations on 07R HKG are a known phenomenon, hence the broadcast on ATIS. Surely in those circumstances you would brief accordingly and be primed to disconnect the AP as soon as you noticed an abnormal behaviour rather than watching the manoeuvre - the vis was 10k...?
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VHHH 07R is normally used for departure or cargo aircraft as it is next to the freight apron. Unusual to get it for normal arrivals. 07L has frequent windshear so you can't win.
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Is there an RNAV approach available for 07R? Why not prepare for that? Two warnings for glide path fluctuations with more than suitable weather for an RNAV approach makes it the sensible option surely? |
Originally Posted by underfire
(Post 10328981)
Ground prox warning alerted the crew...nothing from ATC?
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In report linked with message above is stated that ATC also informed crew about fluctuation, just before they cleared them for approach.
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Does it make sense to monitor distance v altitude: OH YES!
Wonder why so many of our LTC/TRI/TRE advise cadets and old folks' like me there is no need to do so once GS captured as ILS has a sufficient protected area... Please allow me to do at least the odd check as per old days, it could prevent the EGPWS sounding in the first place, avoiding such a low recovery requirement. |
Does it make sense to monitor distance v altitude: OH YES! Looks like in this case the GS went for a ride and the autopilot obliged. The crew recovered and regrouped. |
Wonder why so many of our LTC/TRI/TRE advise cadets and old folks' like me there is no need to do so once GS captured as ILS has a sufficient protected area... |
If you know there is a possible problem with the G/S signal and no other type of approach is available, why not hand fly the aircraft?
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Is there an RNAV approach available for 07R? Why not prepare for that ? |
You just never know when the technology is going to try to kill you!
Jet Jockey, you'll be put in the sinbin for suggesting that. |
Why not do a LOC approach??
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Downgrading to a LOC approach would be an option.. Relying of a unreliable signal to make an instrument APP is not really my cup of (Chinese) tea. |
Originally Posted by ATC Watcher
(Post 10329143)
ATC is normally not monitoring the glide , just azimuth . In addition even if they did , the transponder mode S ALT will need to be detected normally by a rotating SSR antenna, so would take a few seconds to be displayed and another few to transmit the info which would likely be : XXX check or confirm altitude. , GPWS is much faster . It worked well here. Good reaction from the crew, Lesson to be learned ? Oh yes, these cautions warnings on the ATIS to start with More aimed at waiving responsibility from the Airport, authorities than helping the crews. .
Would probably be prudent to just switch off the glideslope when the ceiling allows LOC approaches, especially if that problem occurs regularly. Or just keep the area in front of the glideslope antenna clear even when the weather is good. And while the reaction to being low was good, being so low in the first place while the runway is in sight not so great though. |
Why not just fix the problem with G/S. It cannot be that difficult. Or just say G/S not available. It is another case of making holes in the system for some one to fall through one day. This time the pax were lucky. Still pilots get blamed for failing to see the ditch.
https://timesofindia.indiatimes.com/...w/66967735.cms |
I thought the same but have seen myself sometimes how the airport relies on pilot feedback to determine the health of the system. Bit of a catch 22
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If the glideslope was unreliable why was it not taken out of service and a NOTAM issued.
Leaving a faulty ILS in service to trap the unwary is dangerous bad practice, someone deserves some serious discipline to be applied. |
Originally Posted by ATC Watcher
(Post 10329143)
ATC is normally not monitoring the glide , just azimuth . In addition even if they did , the transponder mode S ALT will need to be detected normally by a rotating SSR antenna, so would take a few seconds to be displayed and another few to transmit the info which would likely be : XXX check or confirm altitude. , GPWS is much faster . It worked well here. Good reaction from the crew, Lesson to be learned ? Oh yes, these cautions warnings on the ATIS to start with More aimed at waiving responsibility from the Airport, authorities than helping the crews. .
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Originally Posted by Callsign Kilo
(Post 10329115)
Is there an RNAV approach available for 07R? Why not prepare for that? Two warnings for glide path fluctuations with more than suitable weather for an RNAV approach makes it the sensible option surely? https://cimg8.ibsrv.net/gimg/pprune....1dd79ff5fa.jpg https://cimg1.ibsrv.net/gimg/pprune....dae6ad9dbb.jpg https://cimg0.ibsrv.net/gimg/pprune....f318a89451.jpg |
Originally Posted by Jet Jockey A4
(Post 10329226)
If you know there is a possible problem with the G/S signal and no other type of approach is available, why not hand fly the aircraft?
If the glideslope signal is fluctuating it should not be used. ATC should switch it off. |
CDFA ! Rule of thumb: 300 ft per NM (for a 3 deg. descent angle). In this case it makes it quite easy as it is over sea level. |
Oops, do you mean why not fly a RNAV approach? as far as I know they do not have any RNAV approaches in India, and DGCA probably does not allow their pilots (and aircraft) to fly them (?). |
Originally Posted by ManaAdaSystem
(Post 10329742)
And which signal would you follow if you decided to hand fly? If the glideslope signal is fluctuating it should not be used. ATC should switch it off. |
Puzzle me this....
TEM: the threat is the dodgy GS signal, broadcast on ATIS and further backed up by ATC to the crew. How should a crew mitigate this threat to avoid making an error? Fly the LOC only approach (the weather was more than adequate) or if allowed an RNAV approach. It would appear that TEM was not effectively applied by this crew.... |
Originally Posted by Capt Fathom
(Post 10329218)
Sounds good in theory, but not a lot of time to continually be doing your 318.4 times table down final. Even with the table on the chart, it’s not practical to be continually monitoring it, especially in good weather. Speed, thrust and rate-of-descent (and the view out the window) would be the indicators something was amiss. Looks like in this case the GS went for a ride and the autopilot obliged. The crew recovered and regrouped. Reading your post and I'm starting to realize why guys have the speed brakes out diving to 2000' 25 nm from the runway. And yes, after leveling off intercepted a false glide slope and didn't realize it. Where is this DTG function on the FMC? PROG page 1/4. Here's the really sad part - they were VFR (2214Z) - VHHH 192230Z 09012KT 9999 FEW022 SCT035 24/19 Q1019 NOSIG= VHHH 192200Z 09010KT 9999 FEW020 SCT030 24/19 Q1018 NOSIG= |
Here's the really sad part - they were VFR (2214Z) |
Does anyone look out of the window ?
If the approach is correct the touchdown point will always be at the same point on the windscreen. If it in the wrong place it is time to worry. |
There were minimum 2 in the cockpit I assume. .In my (old) days the PF was looking down at the ILS bars,scanning speed/ altitude the PNF was looking outside.and cross checking parameters.
looking at recent accidents and incidents like this one it would seem that many today are all looking at the bars and nobody is scanning the other parameters.or bother to look outside before minimum even when VMC. Is is how the new training is made?. Full trust on automation ? |
A fluctuating signal can bring the aircraft into a bad situation really fast. I’m sorry, but I’m one of those lazy pilots who tend to be a bit relaxed when I fly. I don’t sit there and read out mile vs altitude every single mile when I do an ILS.
A sudden GS pitch down on short approach followed by GPWS and go around. Good call. The GS should not have been on the air. |
I suppose if one was determined to do the ILS but not wanting the aircraft to be following any fluctuations(happens in Seattle as well), they could just use the V/S function while following the glideslope in general. Especially with the weather conditions being beautiful VMC, they could just be mostly visual. Back it all up by confirming 1600 feet when passing VH721, continuing at about 7-800 fpm, checking distance to go versus altitude continues to make sense along with the sight picture out the window.
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punkaolouver finally nailed it.
This is exactly what we do as regular operators into HKG on 07R. Happens frequently. We always shoot the ILS, aware of the possibility of GS fluctuation. The RNAV is available, but we only bother if it's low cloud or vis. If the GS plays up (about 1 in 10 times), just select VS 7-800 fpm or disconnect and hand fly. Easy peasy. However, this is common sense, experience and airmanship we're talking about here... Sadly not something prevalent in many operators in this neck of the woods, especially the airline were discussing or the muppets to the north of us. |
VHHH 192230Z 09012KT 9999 FEW022 SCT035 24/19 Q1019 NOSIG=
Was the PAPI u/s? The overall pattern here is the habitual preference for technoiogy over nature. |
couple of months ago, was also established on the ILS 7R, autopilot engaged, stable and all of the sudden aircraft pitched down very rapidly and violently.....immediately disconnected ap, recycled FDs, and able to salvage approach.
Yes they offered Rnav on the Atis but company not authorized for Rnav, and believe Atis said possible GS oscillations- thought they meant it might scallop a little up and down, really wasn't expecting that. |
Originally Posted by Flying Clog
(Post 10330492)
punkaolouver finally nailed it.
This is exactly what we do as regular operators into HKG on 07R. Happens frequently. We always shoot the ILS, aware of the possibility of GS fluctuation. The RNAV is available, but we only bother if it's low cloud or vis. If the GS plays up (about 1 in 10 times), just select VS 7-800 fpm or disconnect and hand fly. Easy peasy. However, this is common sense, experience and airmanship we're talking about here... Sadly not something prevalent in many operators in this neck of the woods, especially the airline were discussing or the muppets to the north of us. I find it hard to accept that this is an ongoing problem, and that nothing has been done about it. A glideslope that has been known to bring aircraft into upsets should never be on the air. NOTAM or no NOTAM. |
That’s why local ATC make a point to verbalise it, ManaAdaSystem! |
That is your view, mine is: That’s why they have an off button for the glideslope. |
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