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)

"possible glide path fluctuation"...possibly this affected things?

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...?

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.

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. .

In report linked with message above is stated that ATC also informed crew about fluctuation, just before they cleared them for approach.

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.

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?

RNAV approaches in VHHH are approval required, possibly they weren't authorized ? There is a VOR approach available for 07L but not for 07R. Downgrading to a LOC approach would be an option.

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??

My point . ,It makes little sense to me to warn on the ATIS and on the frequency there is a GS problem and leave it to the crews to decide to use it or not. In an ideal Safety conscious world either the GS is U/S or it is calibrated and working.
Relying of a unreliable signal to make an instrument APP is not really my cup of (Chinese) tea.

Looking at airport layout it seems like 07R is the departing runway. So as the weather is good they can land 07R while still having a 747 hold short of the runway on the south side of the runway where the glideslope antenna is located. Which obviously screws up the signal.

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