Air India B788 descends to 200 ft over water at HKG

[Safe-T]

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/615867-air-india-plane-del-arn-gets-stuck-building.html)

[DaveReidUK]

Serious Incident Bulletin 6/2018 (https://www.thb.gov.hk/aaia/doc/Serious%20Incident%20Bulletin%206-2018e.pdf)

[ironbutt57]

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

[underfire]

Ground prox warning alerted the crew...nothing from ATC?

The ac descended rapidly to 200' AGL? Dive to intercept at 2.6nm?

[petrichor]

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...?

[krismiler]

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.

[Callsign Kilo]

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?

[ATC Watcher]

Ground prox warning alerted the crew...nothing from ATC?
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. .

[nebojsar]

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

[Skyjob]

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.

[Capt Fathom]

Does it make sense to monitor distance v altitude: OH YES!
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.

[Callsign Kilo]

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...

I’d say it is taught, certainly my airline has an SOP for it - however this generally happens at 4mn and relates to an OM or chart published point. Certainly carries significantly more relevance when in IMC. Not sure what the cloud ceiling was here but these guys had 10K viz. Still reckon airmanship dictates that the ILS was the wrong choice of approach. Airmanship, now there’s a thing!

[Jet Jockey A4]

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?

[krismiler]

Is there an RNAV approach available for 07R? Why not prepare for that ?

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.

[Capn Bloggs]

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.

[iceman50]

Why not do a LOC approach??

[ATC Watcher]

Downgrading to a LOC approach would be an option..
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.

[wiedehopf]

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. .

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.

[Hi_Tech]

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/business/india-business/air-india-grounds-two-pilots-after-its-hong-kong-flight-descended-rapidly-probe-ordered/articleshow/66967735.cms

[Smooth Airperator]

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

[The Ancient Geek]

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.

[aterpster]

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 the U.S. they do where TRACON or en route radar is available: MSAW and EMSAW. This was an issue in the KAL 801 747 CFIT at Guam, because ATC had the MSAW disabled.

[aterpster]

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?
Only RNP AR. Requires special quals. Here are the four charts for 7R:
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/579x1000/vhhh_7r_cat_ii_9204fa0445ede3b740f44bad7d69991dd79ff5fa.jpg
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/579x1000/vhhh_7r_ils_9570256295f1a03542513a303ab136dae6ad9dbb.jpg
https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/579x1000/vhhh_7r_rnp_z_2109a1f46b3395d0a08d0bf35a283df318a89451.jpg

[ManaAdaSystem]

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?

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.

[avionimc]

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.

[avionimc]

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 (?).

[Jet Jockey A4]

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.

Well the autopilot doesn't think it just follows the signal whether it is correct of false... A pilot who has some common sense (and it seems a lot of them don't), who is tracking a G/S with a regular rate of descent on a stable approach will not all of a sudden, if he is competent, simply push the nose hard over to follow a G/S towards the sea especially if he was warned twice by ATC prior to the approach that there might be some problems with the G/S.

[The Puzzler]

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....

[misd-agin]

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.

Oh please. FMC has track distance to the airport. From once it's loaded, even if it's 16 hrs away. It's simple math, 300 x track distance + altitude. It's so simple people can even do decimals for a quick estimate. In this case 2.6 = 2 x 300' = 600' .6 x 300' (standby, left me find a calculator...) = 1800, drop the zero, 180. Now you need to do something with the 180. Well 3 miles is 900', and 2 miles is 600', so do you think you add or subtract the 180' to the 600'? Most people would add that. So 600' + 180' = 780'. Report says they were at 200' so they were approx. 580' below glide slope.

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=

[Hotel Tango]

Here's the really sad part - they were VFR (2214Z)

I would have thought they were flying IFR but in VMC.

[The Ancient Geek]

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.

[ATC Watcher]

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 ?

[ManaAdaSystem]

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.

[punkalouver]

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.

[Flying Clog]

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.

[PJ2]

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.

[casablanca]

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.

[ManaAdaSystem]

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.

It’s easy when you operate in your own backyard, and you have detailed experience with the airport an its systems. Worse if you fly there a few times every year.
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.

[act700]

That’s why local ATC make a point to verbalise it, ManaAdaSystem!

[ManaAdaSystem]

That is your view, mine is: That’s why they have an off button for the glideslope.

[Capn Bloggs]

That’s why local ATC make a point to verbalise it, ManaAdaSystem!
Are you serious?? TURN IT OFF and FIX IT! This industry is dangerous enough as it is without known and accepted traps like this. Rediculous.

[ManaAdaSystem]

How do you local guys fly this ILS approach in minima weather? VS and if the GS suddenly dips down, you continue i VS? Or do you go around? 1 in 10 approaches end up with a go around?
This is an accident waiting to happen.

[wiedehopf]

Are you serious?? TURN IT OFF and FIX IT! This industry is dangerous enough as it is without known and accepted traps like this. Rediculous.

As this thread is still going i thought i would dig a little in the FR24 archives.

It's quite likely the 747 lining up for departure is causing the GS distortion.
So you can't just "fix it", you need to adjust ATC procedures.

(I'm not sure about different antenna types though i believe there are types that are less prone to distortion)

See the following pictures looking at the 20th October at 22:13 UTC

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/1366x768/screenshot_from_2018_12_08_15_56_31_0834dc84672c7db0e005dc6e 7f6a67624015ec49.png
https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/1366x768/screenshot_from_2018_12_08_16_01_42_586ab6e6f03c83b7809f7cdb 3a23ba1ea34f5587.png

[ManaAdaSystem]

Possible, but I think this would have been looked into a long time ago.
ILS systems are flight tested on a regular basis. Don’t know the source for the NOTAM, pilot reports or test results?

[FlightDetent]

1) Move the holding point before the U-turn, and introduce "Line up behind" [ICAO standard since long ago].

I was actually about to say a bit in defence of the crew, but seeing the graph by wiedehofp, now I am glad I did not.

[pattern_is_full]

This is not an inherent problem with the GS equipment at VHHH. It is due to departing aircraft on the ground proceeding into the ILS Critical Area and interfering with the GS signal.

Clearly well-known to the authorities, since they have carefully painted an ILS HOLD line on taxiway K, abeam the GS antenna (see top image, post #43, and the airport diagram). And not uncommon at other airports.

If the ceiling is below 800' and/or visibility is below 2 miles, and an aircraft is on the ILS inside the OM, ATC should not permit an aircraft (or other vehicles) to pass that hold line. because it is well-known that that can make the GS reception unreliable.

However, on this day, the weather was well above those requirements, and ATC was not required to protect the GS signal.

Therefore it is up to landing crews, well-informed by charts, NOTAMs, and ATC verbal warnings that the GS could be unreliable as departing aircraft interrupt it periodically in good weather, to use common sense and not be automation-dependent. Use the ILS for guidance if you wish, but be prepared for a honking great 747F to pass in front of the antenna and foul up the GS signal. Be ready to hit the VS HOLD button, or cancel the A/P altogether and hand-fly the rest of the approach manually and visually.

[ManaAdaSystem]

This is not an inherent problem with the GS equipment at VHHH. It is due to departing aircraft on the ground proceeding into the ILS Critical Area and interfering with the GS signal.

Clearly well-known to the authorities, since they have carefully painted an ILS HOLD line on taxiway K, abeam the GS antenna (see top image, post #43, and the airport diagram). And not uncommon at other airports.

If the ceiling is below 800' and/or visibility is below 2 miles, and an aircraft is on the ILS inside the OM, ATC should not permit an aircraft (or other vehicles) to pass that hold line. because it is well-known that that can make the GS reception unreliable.

However, on this day, the weather was well above those requirements, and ATC was not required to protect the GS signal.

Therefore it is up to landing crews, well-informed by charts, NOTAMs, and ATC verbal warnings that the GS could be unreliable as departing aircraft interrupt it periodically in good weather, to use common sense and not be automation-dependent. Use the ILS for guidance if you wish, but be prepared for a honking great 747F to pass in front of the antenna and foul up the GS signal. Be ready to hit the VS HOLD button, or cancel the A/P altogether and hand-fly the rest of the approach manually and visually.

It’s OK then. Until an aircraft nosedives into the ground.
Then they will fix it.

[ATC Watcher]

Therefore it is up to landing crews, well-informed by charts, NOTAMs, and ATC verbal warnings that the GS could be unreliable as departing aircraft interrupt it periodically in good weather, to use common sense and not be automation-dependent. Use the ILS for guidance if you wish, but be prepared for a honking great 747F to pass in front of the antenna and foul up the GS signal. Be ready to hit the VS HOLD button, or cancel the A/P altogether and hand-fly the rest of the approach manually and visually.
Use common sense ? since when common sense is used as a mitigating factor for a deficiency in aviation ? The only valid reason I see to do that is to increase capacity , i.e. money/greed.
If as you said , this only applies in good weather, then say " G/S unserviceable "during that period. You protect yourself as ATC and it is clear for all crews. Because if as ManaAdaSystem prediction above do materialize one day , the guys that authorized this will most likely end up somewhere very unpleasant. .

[nike]

1. HK runs single runway ops overnight into the early morning. You can expect to land on 07R on certain days.

2. If the weather is good, ATC will not protect the ILS sensitive areas.

3. There is no need to fly an ILS in good weather, other approaches are available.

4. The GS fluctuations are reported via a Digital ATIS....you can get this outside of VHF coverage unlike other airports...so you can spend the 2-15hrs of your flight inbound coming up with a plan...there is no surprise here.

5. If you still choose to fly an ILS, you have accepted the risk, best have a plan if you encounter an aircraft upset event. Your decision.

6. If anything needs fixing in HK, it is the extremely inefficient airspace....particularly for arrivals from the north....and there is a 3rd runway under construction.

7. GS fluctuations during single runways ops in the late night period in VMC is a minor issue easily managed by experienced crew....ie don't fly the ILS!

[Flying Clog]

Indeed, if the instructions above are too hard to follow, then maybe flying isn't for you and you should consider another career choice.

It's not that bloody difficult snowflakes.

[Capn Bloggs]

We have holding points right in the beam and I've never had a duck-dive on final. Something cockeyed here...

[ironbutt57]

We have holding points right in the beam and I've never had a duck-dive on final. Something cockeyed here...

have to agree with you on this one Bloggs...something not right

[FlightDetent]

Does the fluctuation, in anyone's opinion, explain what we see on the profile as recorded on FR24? I experienced some G/S fluctuations at SVO for the very same reason of GP antenna shielding, but the overall effect was very different.

The second approach, just starting the final descent

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/900x1042/2018_12_09_15__70d03f02f964e5100cccbbc3e40723973133b109.png


Same position but on the first approach. Already well below profile, -2000 fpm and keeps descending

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/900x966/2018_12_09_18__c45be1cd268d881b239de175ee59e0acbe12550d.png

First approach, 5 miles out: 400 ft AFE and still -2000 fpm

https://cimg3.ibsrv.net/gimg/pprune.org-vbulletin/900x1003/2018_12_09_8__0eeb2761fe8bd53028795323b6d90e3790d5ce7d.png

And the correction is … creepy.


https://cimg7.ibsrv.net/gimg/pprune.org-vbulletin/510x488/beze_jm_na_6a625212571a75218442854d14d61f28fb6ca142.jpg

[aterpster]

It’s OK then. Until an aircraft nosedives into the ground.
Then they will fix it.
It can't be "fixed" if it is a taxiing airplane blocking the GS transmitter during good weather conditions.

[Bleve]

Fluctuating ILS glidepath signals are not uncommon. Usually always caused by large lumps of metal (ie aircraft on the ground) moving between you and the transmitter. I’ve seen it at VHHH, KLAX & YSSY. In all cases it has been in VMC and ATC therefore are not required to protect the ILS signals. Pilots are expected to use airmanship and commonsense. Call me old fashioned, but when it has happened to me I (shock, horror) disconnected the autopilot, looked out the window and hand flew a visual approach.

[masalama]

A wise man (Murphy?)once said , “ If something can go wrong , it will” . Knowing that there’s a deficiency in the system and “hoping” the end user will be able to hack it is OK in some industries but not in aviation IMHO.
As boeing have recently found out with their MCAS , don’t make a hole in the cheese and cover it up with tape , someone’s gonna find a way to line up the holes 😳😳
masalama👍👍

[aterpster]

A wise man (Murphy?)once said , “ If something can go wrong , it will” . Knowing that there’s a deficiency in the system and “hoping” the end user will be able to hack it is OK in some industries but not in aviation IMHO.
As boeing have recently found out with their MCAS , don’t make a hole in the cheese and cover it up with tape , someone’s gonna find a way to line up the holes 😳😳
masalama👍👍
It's called reading the notes. If we have to hope an airline pilot will read the notes, then this profession is no longer a profession.
https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/636x513/vhhh_note_a759bf43195a317b48da5bb2eb57f179d209b765.jpg

[misd-agin]

1. HK runs single runway ops overnight into the early morning. You can expect to land on 07R on certain days.

2. If the weather is good, ATC will not protect the ILS sensitive areas.

3. There is no need to fly an ILS in good weather, other approaches are available.

4. The GS fluctuations are reported via a Digital ATIS....you can get this outside of VHF coverage unlike other airports...so you can spend the 2-15hrs of your flight inbound coming up with a plan...there is no surprise here.

5. If you still choose to fly an ILS, you have accepted the risk, best have a plan if you encounter an aircraft upset event. Your decision.

6. If anything needs fixing in HK, it is the extremely inefficient airspace....particularly for arrivals from the north....and there is a 3rd runway under construction.

7. GS fluctuations during single runways ops in the late night period in VMC is a minor issue easily managed by experienced crew....ie don't fly the ILS!


5. If you still choose to fly the ILS WHILE ON THE A/P you have accepted the risk.

Glide slope blanking by aircraft taking the runway is common. As is LOC fluctuations as a plane clears the runway. This isn't new.

Are those sink rates and altitudes correct? 2,600 FPM at 1350'? 1,900 FPM at 525'? Who's minded the store?

If the ILS signal, or autopilot, gets twitchy it's taken out of the loop ASAP.

[aterpster]

7. GS fluctuations during single runways ops in the late night period in VMC is a minor issue easily managed by experienced crew....ie don't fly the ILS!

During my career my company required we fly the ILS, if the runway had one. We often didn't couple. Hand flying works quite nicely, or at least it used to. And, there are no other approaches to 7R unless you are RNP AR qualified.

[The Ancient Geek]

It can't be "fixed" if it is a taxiing airplane blocking the GS transmitter during good weather

It just needs more cooperation between Ground and Approach. Sit them next to each other.

[ray cosmic]

GLS would solve the issue..

[Long Haul]

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]

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]

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]

Did anyone look out of the window?

[aterpster]

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]

Did anyone look out of the window?

apparently not

[Icarus2001]

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]

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]

I really hope that you are joking.
About 50/50

[Capn Bloggs]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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:

[Flying Clog]

Yup, agree with the above 3 comments. I think we've reached a verdict on this lot.

[nike]

https://www.flightglobal.com/news/articles/sia-777-excursion-at-munich-sparked-by-ils-interfere-454525/


Topical......ATC will not protect the ILS signals if it's CAT 1 approaches in use.....buyer beware.

[aterpster]

In the U.S. weather below 800 and or 2, they will.

[wiedehopf]

Not protecting the signals and allowing departures from the same runway is quite something different.

[nike]

Eh?

If the signal is not protected and you choose to keep the automatics in....buyer beware.....

[The Ancient Geek]

Traps for the unwary.

[wiedehopf]

A 747 tail taxiing through the glideslope is different from an airplane taking off going through the localizer beam.

The glideslope disturbance is much closer to the antenna so will be a lot stronger.

Also you need to differentiate between the sensitive and critical areas. Or whatever the nomenclature is.
With the 747 in the glideslope the ILS is basically unusable.

With the aircraft taking off crossing the localizer beam the disturbance should be short and less severe.
(So the real important areas were still protected in Munich while that was not the case in HKG
Just wanted to point out the difference)

Anyway while we are on the topic i'll add another incident:
My guess would be that the 747 Air China Cargo that had a runway excursion / go-around at Chicago O'Hare was the same situation as Munich.
(Incident: China Airlines B744 at Chicago on Jun 21st 2018, veered off the runway and went around (http://avherald.com/h?article=4ba33b1c))

[FlightDetent]

Due to the TWY - GS antenna configuration the same was an issue at SVO for 25L (it's been a while).

Their ATC solution was to declare NDB apch in progress in VMC+ conditions, when the close holding points were needed to keep high flow. .

Not saying better or worse, just in agreement with w. that it is a major issue.

Somewhat related: Approaching LGW behind an A380, the controller would offer an RNAV approach with the standard super-separstion, or an ILS which required (almost) additional 2 NM in trail.

Maybe someone here kept the ILS scales on during the RNAV APCH and observed what was the actual behaviour?

[pattern_is_full]

Due to the TWY - GS antenna configuration the same was an issue at SVO for 25L (it's been a while).

Yes - the geometry of a GS antenna is fixed everywhere - the antenna is, by definition, the place where the G/S beam intersects the ground. ~300m/1000 feet beyond the threshold "piano keys." Thus a taxiway that meets the threshold at 90° (extremely common) will also always be ~300m from the G/S antenna, and risk a holding/taxiing aircraft becoming an obstruction.

Workarounds can only be done by adjusting the taxiways to not lead directly to the threshold at 90°, or changing ops otherwise: displaced threshold; long looping taxiway that connects to the threshold at 0°, all departures from an intersection beyond the G/S antenna; back-taxiing from an intersection for >300m (probably not a good idea when another aircraft is inbound inside the marker - and might still produce interference). Switching to a 6° GS would put the beam angle "above" even tall aircraft that might block the signal - maybe.

All of which produce their own issues.

[nike]

The concept of promoting autolands as the future due to inexperienced crew, fails to consider the busy ATC environment, the lack of ILS signal protection unless weather conditions dictate it, and therefore the potential consequences of conducting auto-coupled approaches in day to day operations.

Piloting skills..... still required.
Minimum 2 crew...still required.

Airline Management have for years belittled/discredited our Profession by reducing T&Cs, looking to increase productivity.
They have believed an increase in automation with a transition to single crew operations on large aircraft as an opportunity to reduce costs, yet time and again we see the realities of operating in an increasingly busy airspace environment prove that there is no quick fix despite the accountants wishes.

[ATC Watcher]

nike :The concept of promoting autolands as the future
I was attending a presentation 2 years ago by an executive of a large European low cost operator on the introduction of the 737-8 max who said that they were planning mandating auto lands on the type where it was feasible in order to reduce go arounds and tyre wear. Did this actually materialize ? never heard anything about it since.

[atpcliff]

Thanks to everyone here that posted. We just flew into HKG for the normal 07L landing. During the arrival, ATC changed our arrival and told us to land on 07R. They gave us the verbal GS warning, as described above. We saw an Emirates aircraft approaching the hold short line, which could disrupt the GS signal. We turned off the autopilot, and followed the PAPIs just in case the GS signal was disrupted, and landed uneventfully. The EK aircraft did not get near the hold short line before we landed, and we saw no GS distruption.

[casablanca]

Often though they are using 7R at night, or early mornings. When it happened to me it was probably the most violent autopilot malfunction I had ever experienced, even though we were familiar with warning will take you by surprise.
Clicked off autopilot And recovered....but when I read possible gs interference this is not what my mind conjured up.

[Sqwak7700]

Would not the simplest solution in HKG be to only line up airplanes on 7R from J and H when using the runway in mixed mode? Just make all GA and Cargo aircraft cross at J6 and join the cue on the north side of the runway. By not using K1 you would avoid any issues.

Or just hold aircraft at the Cat 2 hold. I don’t understand why that is so hard. If you time it right then it makes absolutely no operational impact. If the planes are that tightly spaced, holding at the CAT 2 would not make that much difference to holding at K1.

[Dan Winterland]

This is an issue that has plagued HKG for many years. Now that it's being investigated by the new investigation authority rather than the regulator, something may be done about it.

[misd-agin]

An easy solution is to hand fly and not blindly fly momentary fluctuations in the G/S signal. Otherwise you'd might have to hold every departing aircraft at the CAT II hold line whenever an aircraft is established on the G/S. What impact would that have on the arrival and departure capacity of the airport?

[vilas]

An easy solution is to hand fly and not blindly fly momentary fluctuations in the G/S signal. Even if you handfly the false GS result will be same. It will have to be planned to closely monitor the VS and DME checks. With VIS 9999 better would have been to fly localiser approch with steady FPA.

[act700]

atpcliff

you did what...disconnect the a/p...in Asia? Are you insane?

[Jet Jockey A4]

LOL... I know you are being sarcastic (well I hope you are) but the real problem remains all those pilots (not just Asians) that can't fly and land an aircraft in visual conditions without the help of on board electronics (autopilot, Fight Director, etc) or external aids (GPS, ILS etc).

There are way too many pilots today that have no common sense, no real stick and rudder abilities and are nothing but little programmed robots them selves that cannot think outside the box and once a simple problem is encountered and it falls outside "their" programmed training, all things fall apart.

[petrichor]

BANG ON FC! Some of the comments here are a trifle worrisome:ugh:

[misd-agin]

With the a/p off, and basic flying skills, the pilot wouldn't descend at the rates this flight did with an erratic G/S signal. Maintaining a constant pitch attitude, and rate of descent, would be fine. And there's something called the VASI/PAPI that is a great visual que. It just requires the pilot to cycle between looking outside, and inside, the cockpit.

We kid about "what's it doing now" or "it's doing it again" but it's said when we read reports about guys just watching the automation work poorly when lower levels of automation are clearly needed.

Post #53, if it's accurate, shows a destabilized approach, for at least 25 seconds, at 1125' AGL with a sink rate of 1,800 FPM, and 1,900 FPM at 525' AGL, on a coupled approach. In what universe is that ever normal?

[vilas]

Missed_again
The incident is not nnecessarily due to lack of basic flyin skill. Any normal ILS approach preparation should take into consideration FAF altitude and distance, average ROD and some altitude Vs DME checks and during execution monitoring that it's happening. Even when they were made aware of a threat they didn't seem to have evaluated it so they didn't have any plan to tackle it. That is why they didn't notice the ROD and DME VS height error which they should have monitored even otherwise.They were simply unaware that anything is amiss till the GPWS sounded which is very poor flying. Without that awareness even manually they would have blindly followed the false GS with same result and if they were aware then even with auto pilot on it was possible to prevent it.

[Jet Jockey A4]

LOL... Please stop with all the excuses! This is total BS!

If a pilot flying an aircraft manually decides to follow a false capture of a G/S and start descending at that kind of rate prior to the usual G/S intercept point and only stops because of an EGWPS warning then both pilots should be terminated!

What are we paid for? What are you trained to do? Where is your airmanship? When flying an aircraft you just can't be sitting oblivious to nothing and let the automation fly on its own without supervision.

It is very clear that this crew did not take seriously the warning on the ATIS nor the warning from ATC and allowed a minor situation to develop into a possible catastrophe and that perhaps only the EGWPS saved the day.

Brief the approach, brief for the warnings and BE READY to react to any problem, no excuses!

You people with all these excuses make me sick!

End of rant.

[FlightDetent]

That's where we differ, vilas. Following a G/S with 2000 FPM through 1000 feet AFE (stabilization criteria, anyone?!! if nothing else for Pete's sake) IS a LACK OF FLYING SKILL. Not of handling skills necessarily (is that what you meant perhaps), but the cognitive and situational awareness as well as predicting the trajectory in 4D is completely missing = no flying skill.

1125' AGL with a sink rate of 1,800 FPM, and 1,900 FPM at 525' AGL, on a coupled In what universe is that ever normal? For the record here, I no longer believe an (untrapped) G/S fluctuation is all of the story here. Have no better explanation, but refusing to accept they would watch it go down like that. Let's see.

[pineteam]

Last week, I offered my colleague to do an ILS raw data approach coming back to our homebase; He is a new Fo but had more than 2000 hours on type. He decided to fly bird off but with A/THR. While intercepting the localizer around 3000 feet, we had a crosswind of about 26 kt ( Wind on ground was light) and he aligned the aircraft on the heading bug who was set on his request to the runway track. Very quickly we start drifting away from the centerline and I told him ''Bro you need to turn to the right, look at the track diamond''. He got confused, and barely turn right then left again and we drifted away even more. Now we were like 2300 feet and 2 dot+ out from the localizer. We were in IMC conditions still, it did not help the poor fellow. shortly after the tower called us to confirm we were established... LOL. Under the panic, and while I was talking to ATC he jumped on the FDs, the APP p/b and engage the AP which recaptured the Localizer. He apologized for it and realised how poor his handling and situation awareness could be. And that was on a fairly good day with A/THR. I let you now imagine how catastrophic it could have ended with 2 guys like him in front in the event of a serious failure resulting in alternate law....

[vilas]

Flight Detent
Yes, by basic skill I thought missed_again meant ability to follow LOC and GS manually. But I think you missed my following statement.They were simply unaware that anything is amiss till the GPWS sounded which is very poor flying.

[aterpster]

No excuse to bust LOC-only minimums!

[vilas]

It may be interesting to know what the crew did the second time. Did they just repeat what they did the first time and were just lucky that the glideslope didn't fluctuate or if they did something different then why not the first time? By the time the report is out(about two years) nobody will remember the incident.

[tcasblue]

Seems to have happened again, although not sure how serious it was:

C-FNOH, an Air Canada Boeing 787-9 was conducting flight ACA7273 from Toronto/ Lester B.
Pearson Intl (CYYZ), ON to Hong Kong Intl/ Chek Lap Kok (VHHH). On final approach, in visual
meteorological conditions, the aircraft deviated below the glideslope. The glideslope was
reestablished at approximately 900 feet ASL. The flight landed without further incident.

[DaveReidUK]

The flight trackers would appear to support that trajectory. Height at 4 DME was approximately 950' AAL.

[vilas]

All these Hongkong incidents of GS fluctuation are handled very unprofessionally risking precious lives without reason. The approach needed to be planned on threat assessment. The good old FORDEC would have you land without problem. What's the threat ? GS fluctuation may cause the AC to dive or climb. What are the options? 10km visibility allows you to do
1. LOC only approach and B787 has even IAN or
2. purely a visual approach or
3. Select ILS but don't arm approach instead use LOC. You can set up required descent you can track GS when OK and ignore it when misbehaving. When visual just go ahead and land.
Is this rocket science? Just flying manually will not solve the problem it will hit sea manually.

[Chronic Snoozer]

Is ‘threat assessment’ a euphemism for airmanship?

[vilas]

It's not euphemism. Airmanship is a vague word in a sense. It encompasses everything that pilot does or should do. It's doesn't define specific situational remedies. That's why the TEM has been developed. It's systematic way to identify the problem and enumerate precise steps 1,2,3,4 to tackle it.