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SAR S-92 Missing Ireland

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SAR S-92 Missing Ireland

Old 16th Apr 2017, 07:43
  #1041 (permalink)  
 
Join Date: May 2002
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Originally Posted by jimf671 View Post
We know what their heading was in the last seconds but their path across the ground may have brought them along the edge of the light's red sector.

So what would they have seen and what would they have taken from that? Every 500m at 80 knots they should see a flash of white or red. Was the cloud base really 300 to 400 feet or was it below 282 feet?
The surface wind was 220deg/20kt and they were heading 122deg/80kt i.e. almost all right crosswind which explains the track shown in fig 6 of about 110deg. The transcript notes the pilot saying "groundspeed gonna start increasing", I wouldn't have thought by much as it's almost all crosswind.

The aftercast says 300' cloud base, and their baro altimeter was indicating 300'. So they would have been just in/out of the bottom of it at 200' radalt with mostly downward visibility. But I would have thought at that short range, even if the light was 80' deep in cloud, the white light of the lighthouse would have lit them up like a christmas tree at least once before they finally saw the rock maybe a second or 2 before impact (they were on the seaward white side of the lighthouse).

I'm surprised the pilot said nothing in the last 14 seconds of the recording, 9 seconds of which was post impact. I suspect the "we're gone" comment from the co-pilot came about one second after they hit the rock, which were the last words recorded from any crew member.
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Old 16th Apr 2017, 08:04
  #1042 (permalink)  
 
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Originally Posted by cncpc View Post
A girl...

...Once that is done, and they are at 200 feet, and they think they are on a procedure in which BLKMO is next, they are doomed unless the system gives them adequate warning of what is out there that they are unaware of and they can recover from the brink...
The things available to save them were:
1. planning,
2. outside visual reference, and
3. aircraft systems.

Planning didn't work because it's a certainty none of the four crew saw the 282' spot height at BLKMO that was marked on their chart. And if there was a note about it written in the supporting text of the chart - which there should have been - they didn't see that either.

That leaves them to the mercy of outside visual reference, and aircraft systems to save them. It's reasonably certain they didn't see the white flash of the lighthouse, likely because nobody was looking forward outside despite being on a visual segment. If the weather was that low that they couldn't see ahead of them they shouldn't have been on a visual segment.

So now they are down to the mercy of aircraft systems to save them. The systems available to them were:
1. radar
2. FLIR
3. search light
4. EGPWS

The radar should have given them ample warning of land directly ahead. It's inexplicable to me how the radar didn't save them, other than operator error.
The FLIR, via rear crew advisory, gave them 14 seconds notice of the rock ahead of them.
The searchlight might have been useful to them, I suspect it wasn't on...if I'm flying around low level at night I like to have the big light on. Maybe there were operational reasons it wasn't on, I don't know.
And finally, the EGPWS. I'm a complete novice on this system, but from the little I understand, the "low altitude" function was enabled which significantly reduces boundary warnings. However, mode 6 was still available to them which enables an "ALTITUDE ALTITUDE" callout. And that's exactly what they got 27 seconds before impact, and again at 2 seconds before impact. My reading of it the EGPWS was doing exactly what it was programmed to do, despite the terrain data issue which has been highlighted. The comments column in the CVR transcript attributes this warning to the radalt. As I mentioned a few pages earlier, I've never seen a radalt associated with an ALTITUDE warning, I doubt very much that the radalt initiated this warning in this instance, it was the EGPWS issuing the warning exactly as it was designed to do for the mode it was commanded to be in. An ALTITUDE ALTITUDE warning from a EGPWS must be responded to by crew avoiding action as set out in SOP. But as I said, I'm a novice on this aspect.

If all these things don't save you, and any one of which would have saved them, I don't know what else to say.

Last edited by gulliBell; 16th Apr 2017 at 08:52.
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Old 16th Apr 2017, 08:21
  #1043 (permalink)  
 
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Planning a landing at 2am, cloud at 300', 100 miles from your home base, you will be looking for a formal procedure, paper or FMS. The question is, what formal procedures for Blacksod were available in R116?


'APBSS' clearly was. Was this the only formal procedure available?
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Old 16th Apr 2017, 08:29
  #1044 (permalink)  
 
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cpnpc - you seem slightly obsessed about the procedure being from LS (blackrock) to LS (blacksod).

Why would a company that doesn't do lighthouse transfer work and can't land the S-92 at Blackrock because the LS is too small, have a procedure to go from Blackrock to Blacksod?

We all agree the procedure is poor and that they didn't need to descend to 200' until much later in the route but it isn't a VFR procedure - why on earth, if you were VMC and coming from the East, would you fly 10 miles West past your intended LS (Blacksod) ?

It is quite clear it was intended as a poor weather/night procedure - just not well written or depicted on the page.
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Old 16th Apr 2017, 08:35
  #1045 (permalink)  
 
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Yup

Originally Posted by gulliBell View Post
The things available to save them were:
1. planning,
2. outside visual reference, and
3. aircraft systems.

Planning didn't work because it's a certainty none of the four crew saw the 282' spot height at BLKMO that was marked on their chart. And if there was a note about it written in the supporting text of the chart - which there should have been - they didn't see that either.

That leaves them to the mercy of outside visual reference, and aircraft systems to save them. It's reasonably certain they didn't see the white flash of the lighthouse, likely because nobody was looking forward outside despite being on a visual segment. If the weather was that low that they couldn't see ahead of them they shouldn't have been on a visual segment.

So now they are down to the mercy of aircraft systems to save them. The radar should have given them ample warning of land directly ahead. It's inexplicable to me how the radar didn't save them. The other aircraft system available to save them was the FLIR, and that, via rear crew advisory, gave them 14 seconds notice of the rock ahead of them. The searchlight might have been useful to them, I suspect it wasn't on...if I'm flying around low level at night I like to have the big light on. Maybe there were operational reasons it wasn't on, I don't know.
"It's explicable to me how the radar didn't save them." That's my read - and I did the same stuff with 212's, 76's, 61's and 214ST's for many years.
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Old 16th Apr 2017, 08:47
  #1046 (permalink)  
 
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Originally Posted by [email protected] View Post
..
Why would a company that doesn't do lighthouse transfer work and can't land the S-92 at Blackrock because the LS is too small, have a procedure to go from Blackrock to Blacksod?

.
Exactly! That's exactly the point. Why was that formal procedure available when self-evidently it wasn't fit-for-purpose?

Aside weather radar, EGPWS, NV, FLIR, moving maps, Black Rock light and paper maps that may have saved the day, if it was the only formal procedure available the strategy 1) let down to 200' 2) follow the procedure will have the inevitable consequences.

If it wasn't the only formal procedure available, one question is: why was APBSS chosen?

Last edited by catch21; 16th Apr 2017 at 11:11.
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Old 16th Apr 2017, 08:59
  #1047 (permalink)  
 
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Gullibell

I doubt very much that the radalt initiated this warning in this instance, it was the EGPWS issuing the warning exactly as it was designed to do for the mode it was commanded to be in. An ALTITUDE ALTITUDE warning from a EGPWS must be responded to by crew avoiding action as set out in SOP. But as I said, I'm a novice on this aspect.
The "Altitude; Altitude" warning is directly triggered by the radalt. It has nothing to do with the EGPWS system.

It is triggered by descending below bugged height. If you have the radalt bug at 180' and you go below that height you get the "Altitude; Altitude" warning.

The reason it is "Altitude; Altitude" and not "Check Height" is because it uses "American English" and they don't understand the difference between height and altitude.

You state that you are a novice but you are happy to make statements that are factually incorrect and based on nothing but assumption and your limited knowledge of other aircraft systems.

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Old 16th Apr 2017, 09:21
  #1048 (permalink)  
 
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Gullibell, the aircraft I fly has much the same equipment and avionics as the R116, including the exact same model of EGPWS. Descent below the preset RADALT height (in this case 180') will cause an "Altitude, Altitude" warning from the RADALT. There is no 'Altitude, Altitude" aural alert associated with the EGPWS. Some of the terrain associated alerts are "desensitised" when landing gear is lowered. The crew of R116 selected LOW ALT mode on the EGPWS. I don't know about R116 but in the A/C I fly it is only possible to display either the EGPWS page or the weather radar picture, not both on the same display. If your display is in weather mode and an EGPWS alert is triggered the display will automatically switch from weather to TAWS. Obviously you don't want to suddenly lose your radar picture at a vital stage of a rig approach or when using radar for weather/terrain avoidance so LOW ALT is enabled to reduce the threshold for EGPWS warnings. It seems counter intuitive to desensitise your EGPWS when flying at low altitude but that is often what is called for.
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Old 16th Apr 2017, 09:36
  #1049 (permalink)  
 
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Originally Posted by Mark Six View Post
Gullibell, the aircraft I fly has much the same equipment and avionics as the R116, including the exact same model of EGPWS. Descent below the preset RADALT height (in this case 180') will cause an "Altitude, Altitude" warning from the RADALT. There is no 'Altitude, Altitude" aural alert associated with the EGPWS. Some of the terrain associated alerts are "desensitised" when landing gear is lowered. The crew of R116 selected LOW ALT mode on the EGPWS. I don't know about R116 but in the A/C I fly it is only possible to display either the EGPWS page or the weather radar picture, not both on the same display. If your display is in weather mode and an EGPWS alert is triggered the display will automatically switch from weather to TAWS. Obviously you don't want to suddenly lose your radar picture at a vital stage of a rig approach or when using radar for weather/terrain avoidance so LOW ALT is enabled to reduce the threshold for EGPWS warnings. It seems counter intuitive to desensitise your EGPWS when flying at low altitude but that is often what is called for.
Although as long as TAWS is displayed on a screen it wont 'pop up' and replace your weather radar, this can be done by displaying TAWS in the ARC mode of the PFD, then you have both TAWS and Weather on the screens side by side.
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Old 16th Apr 2017, 09:41
  #1050 (permalink)  
 
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Originally Posted by [email protected] View Post
cpnpc - you seem slightly obsessed about the procedure being from LS (blackrock) to LS (blacksod).

Why would a company that doesn't do lighthouse transfer work and can't land the S-92 at Blackrock because the LS is too small, have a procedure to go from Blackrock to Blacksod?
Nonsense. Obsessed?

I'm not obsessed at all. It is a VFR arrival departure procedure from helipad to helipad. I have no idea why you don't want to admit that, yet you make the strongest argument that it is.

You are the one who asks, quite correctly, why a letdown procedure would be centered over the highest point out there in the ocean. BLKMO is marked because it is a helipad. Just like Blacksod is marked.

Who cares about the S92 not being able to land there? Is that the only questionable thing in this whole mess? Helicopters transit quite regularly between Blacksod and Black Rock. At some point, CHC may have operated helicopters that can be operated there. Other agencies of the Irish government may provide the helicopters. The route may have been designed before the S-92's and added to CHC's route book.

How to fix this. Put large black letters at the top of APBSS that say "For VFR use only". And for good measure "No PT" beside BLKMO.
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Old 16th Apr 2017, 09:45
  #1051 (permalink)  
 
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Originally Posted by helicrazi View Post
Although as long as TAWS is displayed on a screen it wont 'pop up' and replace your weather radar, this can be done by displaying TAWS in the ARC mode of the PFD, then you have both TAWS and Weather on the screens side by side.
Absolutely correct. Was just trying to keep it simple and explain why the crew may have selected LOW ALT mode. Mind you the RFM states that LOW ALT is not to be used in IMC except during a rig approach.
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Old 16th Apr 2017, 09:49
  #1052 (permalink)  
 
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Originally Posted by Mark Six View Post
Absolutely correct. Was just trying to keep it simple and explain why the crew may have selected LOW ALT mode. Mind you the RFM states that LOW ALT is not to be used in IMC except during a rig approach.
I was just making the point before the 92 slayers jump in!
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Old 16th Apr 2017, 10:40
  #1053 (permalink)  
 
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Originally Posted by gulliBell View Post
And finally, the EGPWS. I'm a complete novice on this system, but from the little I understand, the "low altitude" function was enabled which significantly reduces boundary warnings. However, mode 6 was still available to them which enables an "ALTITUDE ALTITUDE" callout. And that's exactly what they got 27 seconds before impact, and again at 2 seconds before impact. My reading of it the EGPWS was doing exactly what it was programmed to do, despite the terrain data issue which has been highlighted. The comments column in the CVR transcript attributes this warning to the radalt. As I mentioned a few pages earlier, I've never seen a radalt associated with an ALTITUDE warning, I doubt very much that the radalt initiated this warning in this instance, it was the EGPWS issuing the warning exactly as it was designed to do for the mode it was commanded to be in. An ALTITUDE ALTITUDE warning from a EGPWS must be responded to by crew avoiding action as set out in SOP. But as I said, I'm a novice on this aspect.
So much for me taking the time to give the exact aural alerts (post #1008, which you acknowledged in #1028).
Maybe I should have answered what you asked then: "Yes, it is the behaviour of the S92!"

Mode 6 is a 'non-database' mode of the EGPWS, which uses RADALT height as the primary input. I refer to post #1008 for its calls.
The EGPWS look ahead alerting mode (which uses the database) gives "CAUTION TERRAIN", or "WARNING TERRAIN" calls, depending on the 'time to impact' calculated.
The comments column in the CVR transcript is correct.

Only 1600 hours on S92, what do I know?
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Old 16th Apr 2017, 10:47
  #1054 (permalink)  
 
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Coastal radar navigation from the last millennium

25 Years ago, GPS was in its infancy as far as helicopters were concerned. Indeed, DECCA was still the primary navigation tool employed by helicopters involved in Oil and Gas and SAR both in the U.K. and Ireland. DECCA had moved on from the MK 19 roller map to the RNav1 and later the RNav2 computers but they were point-to-point navigation systems. There were no moving maps in helicopters in the 1990s. There was also no electronic nav kit in the back of civilian SAR S61s.

Coastal Navigation and let-down procedures for SAR using a point-to-point RNav2 computer was fraught with danger. Particularly when using DECCA as it was prone to atmospheric interference on that dark and stormy night when you would be quite possibly using it in anger.

For this reason, your position had to be confirmed against a separate source and this was the radar. Putting a waypoint on a piece of rock or a headland confirmed your position. If the waypoint appeared under an appropriate shaped radar return that cross referenced with the paper map you were holding you were where the DECCA RNav thought you were and let-down could proceed safely.

Back in 1995 the SAR contract was operated by Irish Helicopters and they had a waypoint on Black Rock as an IP for a let-down to Black Sod. It was called something different then to the one CHC use now but it was on the rock for the reasons I give above.

It was to confirm your position in an S61 using a generally good but possibly unreliable DECCA nav system and a good distance out from Black Sod to allow height loss after over flying the rock.

It seems that a legacy from a past generation using past generation kit was left in use and the seeds of this tragedy were sown in the early 1990s.

I hope this may shed some light on how this came about from a historical perspective and why there was a waypoint on Black Rock and not mid channel.

Last edited by XA290; 16th Apr 2017 at 11:19.
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Old 16th Apr 2017, 10:59
  #1055 (permalink)  
 
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All that fancy kit, and seemingly using aircraft modes because they CAN be used, rather than using the safest mode to achieve the safest outcome. Whats wrong with looking at a chart, having a published inbound heading with respect to terrain/obstacles and flying an OBS approach, 3nm 1000ft, 2nm 700ft, 1nm 400ft, and either a sensible MDA/H, or in SAR world, continuing to a reduced MDH/auto-hover. All this flying along at 200ft still IMC using radar, then apparently ignoring radar returns(!) seems bonkers and totally unnecessary. Maybe they were clear of cloud, but they were essentially IMC. It seems such an unnecessary loss of life, especially for the poor radar operator, who whilst 'unlicensed' from a flight crew perspective, seemed to have the best situational awareness of the immediate danger.

Addition: I don't doubt that it CAN be done safely, of course it can, and has been for years, and remains bread and butter for many of you, but, it can't be the safest way of achieving the objective of landing at a known helipad for a routine fuel stop. At the very least, have a moving map showing actual OS data or marine cartography, that would immediately depict something as substantial as and island when flying 200ft over water. You can get that for $100 on an iPad, and sadly that alone when referenced against the radar return could have prevented this tragedy.

Last edited by SARWannabe; 16th Apr 2017 at 11:14.
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Old 16th Apr 2017, 11:12
  #1056 (permalink)  
 
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Originally Posted by GKaplan View Post

Mode 6 is a 'non-database' mode of the EGPWS, which uses RADALT height as the primary input. I refer to post #1008 for its calls.
OK, I understand that. All I know on this, apart from your enlightenment, is what I read in the report at 3.5.5. When I'm trying to wrangle with that in my head against the "ALTITUDE ALTITUDE" aural alert recorded on the CVR, it makes me assume that that warning was a EGPWS mode 6 warning that may have required a formal crew response by SOP. So it wasn't an EGPWS warning as such, merely an advisory that you have descended below a bugged RA height.
How would an EGPWS mode 6 warning be triggered and indicated, to differentiate it from a descent below bugged RA advisory? I think what you are saying is they are one and the same.
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Old 16th Apr 2017, 11:20
  #1057 (permalink)  
 
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To be slightly pedantic, ALL aural alerts on the S92 except 'AIRSPEED, AIRSPEED' come from the EGPWS box (note: not triggered by - the recordings reside within the EGPWS processor and can be triggered externally as well as internally) So if you lose the EGPWS you lose all system aural warnings.
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Old 16th Apr 2017, 11:20
  #1058 (permalink)  
 
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Originally Posted by gulliBell View Post
OK, I understand that. All I know on this, apart from your enlightenment, is what I read in the report at 3.5.5. When I'm trying to wrangle with that in my head against the "ALTITUDE ALTITUDE" aural alert recorded on the CVR, it makes me assume that that warning was a EGPWS mode 6 warning that may have required a formal crew response by SOP. So it wasn't an EGPWS warning as such, merely an advisory that you have descended below a bugged RA height.
How would an EGPWS mode 6 warning be triggered and indicated, to differentiate it from a descent below bugged RA advisory? I think what you are saying is they are one and the same.

As I understand it, Mode 6 is a customer decided preset altitude read out, and gives the actual altitude (or more correctly height as we know it with reference to rad alt) if the customer has chosen 200 ft to be called in mode 6, then that's what is says, TWO HUNDRED. the preset / default is 'ONE HUNDRED'
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Old 16th Apr 2017, 11:29
  #1059 (permalink)  
 
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I just grabbed the EGPWS manual from our technical library...it helps when trying to understand something like this to have the book to refer to. Here is what it says:

Mode 6 provides audio call-outs for descent below predefined altitudes and minimums. The call-outs produce
aural output indications, but do not produce visual indications.
A “MINIMUMS-MINIMUMS” callout is provided based on the decision height discrete with gear down (less
than 90 Kts or less than 200 ft AGL in fixed gear aircraft). With Low Altitude Mode selected or with gear up
(greater than 90 Kts), the message “ALTITUDE ALTITUDE” sounds when transitioning below the selected
decision height.
An optional input gives the ability to force the Mode 6 audio level to lower audio volume. This lets the aircrew
control the Mode 6 volume level with activation of windscreen rain removal, or if they desire lower volume
call-outs at all times.
The EGPWS uses engine torque sensing to detect autorotation. The autorotation call-outs occur at 200 ft and
100 ft. If the gear is not down by 400 ft, an audio “TOO LOW, GEAR” warning sounds.
An excessive bank angle warning is provided based on Radio Altitude, Roll Attitude and Roll Rate. The
“BANK ANGLE” aural warning is given twice and then suppressed unless the roll angle increases by an
additional 20%.
A tail strike warning function is based on Radio Altitude, Pitch Attitude, Pitch Rate and Barometric Altitude
Rate. The voice message “TAIL TOO LOW” sounds continuously while in the warning boundary. Failure
Annunciations Monitor the EGPWS through an annunciator on the annunciator panel. The GPWS INOP
annunciator illuminates to indicate that a mode in the GPWS function is inoperative or degraded.


And importantly, this written in bold in a CAUTION box

The pilot must maintain visual contact with all terrain and obstacles at all times when using the Low
Altitude mode. The Low Altitude mode must not be engaged during IFR conditions. The look down
angle is reduced with Low Altitude engaged. Warning time is greatly reduced.
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Old 16th Apr 2017, 12:10
  #1060 (permalink)  
 
Join Date: Mar 2007
Location: UK
Posts: 83
Gullibell

I just grabbed the EGPWS manual from our technical library...it helps when trying to understand something like this to have the book to refer to. Here is what it says:
Was it a generic EGPWS manual or the S92A flight manual that you grabbed?

The only reason I ask is because what you describe does not sound like the EGPWS as configured in the S92A. I have been searching for the EGPWS windscreen rain removal mode for years now without success.

As you say "it helps when trying to understand................"

After 50+ posts on this topic you are becoming a bit like white noise now.
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