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Crab,
What if you use one of the SAR modes to make an approach to BKSDC (or some similar point convenient to Blacksod) using a northeasterly heading along the long axis of the inlet? One could incorporate Blackrock as an IAP at which descent from the MSA could be initiated....that would have been pretty much a crosswind approach and a final turn at "C" for the run-in to Blacksod. No one seems willing to discuss what options are available to a CHC SAR crew flying the 92 with its first rate Avionics! I have opined that this flight was operating using old fashioned techniques. If some knowledgeable person can point out the fallacy of my thinking on this Ui am quite willing to listen to what they have to say. Absent that input....I am going to stick with my thoughts. The other Crew (118) appears to have done something different on two occasions that night than did 116. We don't know what it was as it was not set forth by the preliminary report. We do not know what the weather was for 118 on the approaches and landings either. My basic question is simple....Do the CHC Crews by SOP routinely use the full capability of the S-92SAR Avionics available to the Crews? Or....as a matter of policy....or lack of policy....generally use legacy techniques relying upon less than full utilization of the aircraft's capability? Basically.....are they still using S-61 techniques when there are newer and better 92 techniques available? |
What if you use one of the SAR modes to make an approach to BKSDC using a northeasterly heading along the long axis of the inlet? One could incorporate Blackrock as an IAP at which descent from the MSA could be initiated....that would have been pretty much a crosswind approach and a final turn at "C" for the run-in to Blacksod |
PHI and the FAA worked together with Sikorsky to approve a very similar Approach to oil rigs and platforms in the Gulf of Mexico for PHI's fleet of 92's so it appears even the non-SAR 92's have that ability.
PHI began use of the Automated Approach capability in 2013. Even EASA approved the Procedure in June 2015. http://www.prnewswire.com/news-relea...300098781.html |
Originally Posted by [email protected]
(Post 9757668)
And if you try to overlay that procedure on Blacksod, especially with Westerly wind, it just doesn't work - hence the need for a SAR type letdown rather than an ARA.
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But talk of an ARA approach here is nonsense, otherwise they would have reached a decision range, having already instigated an offset, after which they must be visual to be able to continue towards the rig. They were not visual with this waypoint. Never overfly the blob if not visual.
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I'm sure Approach To a Point would have been a credible AFCS option. The RFM only allows IMC let downs over water, but I think a suitable initial approach direction from the SE and reasonably low IAS would have allowed its use.
The Approach to Point (ATPT) mode performs an automatic approach to a hover over a pilot selected target. The position of the target is the next waypoint in the FMS flight plan or as designated by the slew controller. To designate a waypoint, use the slew controller to position the cursor over the desired point on either NAV page and press the middle button on the slew controller. This will put a green square and an “X” over the hooked waypoint. Subsequently, pushing the ATPT button on the MSP will initiate an approach to the hooked waypoint. The ATPT always performs a “direct to” approach and does not turn the aircraft into the wind. The pilot may choose to set an FMS waypoint prior to and down wind from the final waypoint. http://i202.photobucket.com/albums/a...ctc/ATPT_1.jpg When the mode is armed, the aircraft initiates an immediate turn towards the target, engages IAS and RALT, defines an approach line, and determines if there is sufficient distance between the aircraft and target to accomplish the approach. If the approach is engaged and the aircraft is too close to the target for the ATPT profile, the Flight Control Computer (FCC) will disengage ATPT. IAS and RALT will remain engaged and the aircraft will continue toward the target so that the pilot can initiate a MOT over the spot or fly the approach manually. If the distance to the target permits, the aircraft will intercept the approach line and perform a decelerating descent to arrive at a hover over the designated coordinates. If below the approach line when initiated, the aircraft will maintain the present altitude until it intercepts the approach line. The aircraft will maintain the present airspeed until the system commands a 1.8 knots per second deceleration to intercept the approach line at the proper speed. If above the approach line when initiated, the aircraft will descend to intercept the line. The maximum rate of descent while intercepting the approach line is 750 FPM when above 500 feet and 500 FPM when below 500 feet. If the aircraft cannot finish the initial descent before the deceleration is scheduled to begin, the system will discontinue the approach and engage IAS and RALT. During the “on the line” approach, the aircraft will decelerate at a nominal 1.8 knots per second and descend at 200 FPM. Above 100 feet, the maximum allowable descent rate is 400 FPM. Below 100 feet, the maximum allowable descent rate is 200 FPM. The approach will not continue if the aircraft is too close to the target to slow down or too high to descend in time. If the approach discontinues during the “on the line” portion, IAS (above 50 KIAS) or VHLD (below 50 KIAS) and RALT will automatically engage. The ATPT will terminate in a hover over the designated coordinates. The system will initially transition to VHLD when within short range of the coordinates, and then to PHLD when directly over the coordinates in a stable hover. RALT will engage when the aircraft reaches the selected hover height. The default hover reference is 50 feet and can be adjusted from 50 to 150 feet via the HVR RA selection on either DCP. |
Originally Posted by SASless
(Post 9757722)
....as a matter of policy....or lack of policy....generally use legacy techniques relying upon less than full utilization of the aircraft's capability? ...
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Originally Posted by G0ULI
(Post 9757315)
If the route was already preprogrammed into the FMS as a result of previous taskings or appeared as a selectable option...
Hey, someone else has already worked out a routing previously, we'll just follow that. Must be okay, it's stored in the FMS. Can it really have been as simple as that? It could have appeared as a simple, safe option to a crew unfamiliar with the area operating in pretty poor weather conditions. Why reinvent the wheel when someone else has apparently already done all the hard work? Descend to gain sight of the surface over open water, select the route and concentrate on the rest of the mission. An expectation that the route was "safe" because someone must have flown it before, would certainly go a long way to explaining the apparent initial confusion and lack of urgency in changing course in response to the FLIR operator warning of an obstruction ahead. A land based analogy could easily be drawn with professional lorry drivers blindly following sat nav directions and colliding with low bridges or other hazards when it should be obvious that the route is unsuitable. After R116 returned from its top cover on the 8th, having earlier departed Blacksod , the aircraft underwent a 50 hour maintenance inspection. It made only a single one hour flight in the East Coast area before the fatal flight. There is a high probability the waypoints were still in the Euronav system as a recorded previous flight. On the 8th the AIS shows R116 approached Blacksod via BKSDB and BKSDC however it departed Blacksod via BKSDA and BLKMO. (Their westerly track to the FV went about 400m south of Black Rock so BLKMO must lie along this). (Note Sligo R118 never adhered to any of these formal approach/departure routes either on the 8th or 13/14th) So for the R116 crew uncertain of the approach its a simple matter to reverse the previous course to arrive at Blacksod. All GPS and mapping systems use the same SRTM derived terrain elevation models and will either show mainland only and no islands or will show Black Rock at 50ft. Lighthouses do not appear in the IAA AIP or Notams so would not be displayed as an obstacle in the GPS. They do appear on the marine charts. Black Rock was equipped with an AIS beacon but would only show location not height. The Euronav uses a raster (scanned picture) of the 06 Edition 2013 ICAO VFR Chart 1:250000. On the 1:500000 version the 6 deg isogonal line cuts through the third digit of the lighthouses height value making 282 appear as 28ft. Its likely but needs to be verified that the 1:250000 version has the same defect and also the defect text of obscuring the 206ft height of Duvillaun More which would have alerted them to terrain en-route. In the Euronav vector terrain derived from SRTM can overlaid over the raster chart. As many here have stated the crew appeared to believe that Black Rock Mayo was a 28ft small island near waypoint BLKMO and were confident that there were no obstacles or terrain in their path and anyway their GPS TAWS and EGPWS and Radar would alert them. EI |
I've been scratching my head for weeks now wondering what BLKMO stands for, and I think you've just cracked it. It's BLacKrock MayO.
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Best analysis so far.....and very scary.
If this turns out to be the basic scenario then it is heartbreaking. Part of my routine coming on-shift at an EMS base in Texas was to take the Waypoint List out to the aircraft and manually check each Waypoint that was entered into the memory....to ensure each matched the Base Record. When I encountered one that was not on the list I deleted it. A Paramedic saw me doing that and raised hell when I deleted a former Paramedic's house Waypoint from the memory. He refused to consider my advice to him.....that he get it blessed by the GPS Waypoint God and have it added to the approved list and I would be glad to re-enter it. We had a process we used to confirm the accuracy of each Waypoint entered and maintained a record for each one that had not just the Identifier and Coordinates but other information as well to include the Elevation of the Waypoint, location description in general wording, and also references to other Navaids such as VOR's, DME's, and NDB's. That way there was no confusion and at any time the information entered could be confirmed as accurate. |
Stable door.
http://aerossurance.com/helicopters/easa-part-dat-providers/
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From the accident report:
The Commander programmed the “APBSS (Blacksod South) Route” (See Figure No.4 above) into the FMS during the cruise and the Co-pilot confirmed that the route matched the Operator's Route Guide. So they obviously didn't just blithely pull up the waypoints left in the FMS database from a previous task, they deliberately selected a saved route and checked it against the route guide. |
From the accident report: The Commander programmed the “APBSS (Blacksod South) Route” (See Figure No.4 above) into the FMS during the cruise and the Co-pilot confirmed that the route matched the Operator's Route Guide. So they obviously didn't just blithely pull up the waypoints left in the FMS database from a previous task, they deliberately selected a saved route and checked it against the route guide. |
And since the accident report refers to earlier CVR conversations about how long it was since this crew had been to Blacksod, I think it's unlikely that the accident crew were there on 8th.
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Originally Posted by puntosaurus
(Post 9759014)
I've been scratching my head for weeks now wondering what BLKMO stands for, and I think you've just cracked it. It's BLacKrock MayO.
Originally Posted by Emerald Islander
Lighthouses do not appear in the IAA AIP or Notams so would not be displayed as an obstacle in the GPS. They do appear on the marine charts.
Black Rock was equipped with an AIS beacon but would only show location not height. |
Originally Posted by puntosaurus
(Post 9759014)
I've been scratching my head for weeks now wondering what BLKMO stands for, and I think you've just cracked it. It's BLacKrock MayO.
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EASA Decisions on Management of Aeronautical Databases / Part-DAT - Aerossurance
I have reposted ZFDs link as it highlights the database issue |
cncpc. You're absolutely right ! I googled Blackrock before I posted that, but couldn't find anything else, but looking at the map there are four lighthouses in Sligo Bay and one of them is called Black Rock.
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Originally Posted by wiggy
(Post 9759285)
Fixed wing FMS user here somewhat confused . We don't have the ability to look back into the memory (volatile or not) and use a route Bloggs built umpteen days ago, we can however select company approved routes (dep/arr page). I had begin to assume the accident crew had used a company generated route extracted from the database- presumably that was not the case?
The Commander programmed the “APBSS (Blacksod South) Route” (See Figure No.4 above) into the FMS during the cruise and the Co-pilot confirmed that the route matched the Operator's Route Guide. So they obviously didn't just blithely pull up the waypoints left in the FMS database from a previous task, they deliberately selected a saved route and checked it against the route guide. 1- pilot selects APBSS from the 'user routes' page. 2- pilot selects it from the 'company routes' page. 3- pilot enters every waypoint in turn directly. |
GKaplan
Originally Posted by GKaplan
(Post 9759579)
The S92 has the option to pick up a 'crew' route: you get two different pages in the FMS, 'user routes' and 'company routes'. The former can be modified/deleted at will, not the latter (just like you can save 'user waypoints' for repeated use).
Rgds Wiggy |
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