I am reminded by a CFIT in China in the late 90s. This was flying towards the coast, VFR, in a low cloudbase and flew into the steeply rising coastline. The radar was on and from the CVR the crew, being aware of the coastline, had commenced to backtrack towards the sea. From the wreckage the radar was assessed as being on and the tilt was selected at least 5 degrees up.

Flying with the radar tilted is common to avoid ground returns that interfere with returns from cloud formations especially over land. The upwards tilt will mask obstacles directly in front at and below the same height. For example, using the 1/60 rule 1 degree tilt up will hide a 1 foot obstacle 60ft in front; a 100ft obstacle 6,000ft in front. 5 degrees nose up will mask the same obstacle at 1,200ft or under a 1/4 mile. Most radars, when selected to 5 miles or greater, will not define at a 1/4 mile as it will be lost in scanner base scatter. It means that you can fly at a 300ft cliff at 200ft and not be aware of it.

After this event in China we kept the radar at horizontal or lower when operating VFR or at low level. However we still had it cranked up for high level transits to avoid ground returns especially across hilly terrain.

I am not familiar with the S92’s radar or the actions required with it in different procedures but it’s a thought.

unlikely flight track was approach to blacksod LH
 

Yes crab this crew were too experienced to deliberately approach blacksod via such an obstacle and unnecessarily indirect route when time was of the essence.This is a VTOL aircracft afterall.It appears that the approach they actually made was for blackrock Lighthouse and that for whatever navigation system reason they were not at Blacksod.Its late at night ur under time pressure you believe ur at the correct destination the fms says you are and you spot a lighthouse outside this confirms you have arrived and the letdown begins.At night a lighthouse is a lighthouse .

I'm not suggesting it's the optimal method, but given the length of time they operated with S61s it would make sense as a 'legacy technique'. It would be mirroring the standard method of conducting an offshore ARA to a multi-platform field when your destination is in the centre. With the terrain alerts inhibited and the radar tilted up slightly to reduce the sea clutter, and at 10nm or 25nm to give a good view of the bay, it starts to become a little more plausible.

Even if this may be right the Lighthouse is about the highest point of Blackrock. This means they would have had to sink below lighthouse level. Which wouldn't have been a good idea at Blacksod either, the latter one being pretty much at Sealevel.
Even if the track might indicate that the FMS sent them to Black Rock instead of Blacksod it doesn't fully explain why they possibly collided with terrain and definitely collided with the water.

Question: Did the Crew have to manually input the coordinates into the FMS or was it already there?

If they had to manually input the data....what was the source of the data?

Was the Black Rock and Blacksod data next to one another?

What is the SOP used by the Crew when manually inputting such data?

If it is preset in the FMS.....what was there?

Again....could Black Rock have been selected in error some how but the crew have thought it being Blacksod?

Second question: Black Rock is a small bit of land surrounded all around by water where Blacksod is on the shore of a large peninsula.....thus Radar returns would have appeared much different prior to beginning the Approach to Land.

Question: As the approach was being made....as MDA was reached....if Alt Hold was being used....what height above the water would the aircraft be at on the final leg of the approach?

If the weather was such the Black Rock Light House was in cloud....would the crew have been able to see it visually?

Question: What was the weather at Black Rock at the time of the accident?

approach differences blackrock vs blacksod
 

The terrain differences for an approach from the west are very hazardous if you were expecting flat terrain ie blacksod from your chart and you flew heading east towards blackrock lighthouse,in particular its westerley side is very unforgiving.The 2 approaches from the west are illustrated to click on below for comparison.However would the EGPWS not have warned the crew or is it too steep?

Attachment 1922

At night a lighthouse is a lighthouse ....but at night a lighthouse has a characteristic signature from the light, and is far more visible than day. Both were sector lights, b'rock 360 degrees and B'sod dark between 018 and 189 degrees, which is the landward sector. Both flash white and red over their sectors as follows..
B'sod red 189 to 210, white 210 to 018, flash 2, 7.5 sec
B'rock red 212 to 276, white 276 to 212, flash, 12 sec.
No one familiar with maritime could confuse these.

Did you see my post above?

Weather radar.
 

The offshore fit in the S92 is a Honeywell Primus system which includes 2 ground mapping modes, generally used for ARA type approaches. Generally no faffing with tilt during an approach, it's done automatically.
The SAR fit also has a moving map type display from what I've seen in photographs.
I fly offshore in crew change so not sure what modes they would have been using, but find it hard to believe they didn't know where they were with the kit fitted.

Are helicopter Pilots that familiar with light house light codes?

How long would the crew have to visually ID the light house signal that night?

I would suggest the Crew would use other means on-board the aircraft to ID the light house.

yes i see it now 212man thank you so basically the EGPWS is less effective at lower speeds in particular its enhanced or forward facing function

mitchaa This AIS data of the approach appears to show navigation directly to blackrock island.The route taken dosent appear to be useful for a blacksod approach .click to see map below

Attachment 1923

@ Mitchaa
The talk of possible mix up is due to suggestions they made a transmission stating "landing at Blacksod" and within one minute their position was actually tracked to the immediate vicinity of blackrock.
One of the reports concerning debris being described as found at Blackrock lighthouse attributes a comment to a investigation official to the effect that the debris may have washed up there. So, it must actually have been found at sea level, rather than 300 ft above s/l at the lighthouse.

I'm not sure what you are saying. There is no refuelling at Blackrock, it's at Blacksod which is where the crew were intending to land, and announced that they were shortly before contact was lost. However, they were clearly using Blackrock as a navigational reference for some purpose, and I suggest that the last recorded groundspeed and proximity to the rock from the AIS indicates they were not trying to land on it. Similarly, that position indicates that the wreckage did not 'drift there' from another location.

Blackrock is only 12m West of Blacksod, is a potential landmark (lighthouse)/waypoint, hazard (300' cliff) and has a helipad; so is likely to have featured in some way in the approach - but I, like most of us here, have no facts to offer. The crew on the other hand were both highly experienced and presumably knew both these locations/approaches well from many years of practical flying. According to this report they had been there six days earlier

http://www.irishexaminer.com/ireland...er-445271.html

I don't think there is enough information yet to support any theories as to why this happened - there are just too many possibilities and hardly any evidence. It will become clearer in the next days and weeks but, for now this tragedy is simply unexplained.

This article confirms part of the wreckage found on Black rock, but also states no significant impact marks on the island or lighthouse.

In 'hostile conditions', searchers find section of Coast Guard helicopter on Black Rock

What were the regulatory requirements for this flight since it was not directly lifesaving flight but top cover? Would this affect the way such an approach was planned and executed? Crab has told us a bit about how a RAF SAR Force aircraft would have handled approach to Blacksod but this was a civilian aircraft and was this regarded as SAR flight?

In respect of the wreckage found on Blackrock by the accident investigators, PPRuNers may find this interview with Jurgen Whyte, Chief Inspector of the Air Accident Investigation Unit who landed on Blackrock of interest. The relevant piece from last night's RTE 'Prime Time' programme starts at 17:30 with the interview starting at 20:00 and lasting just over 4 minutes.

Prime Time - Thursday 16 March 2017 - RTÉ Player

Even though similarity of waypoint names, callsigns and such-like are recognized as threats in aviation, I don’t see it as plausible that a crew would physically misidentify the two locations whether seen on a map, radar or terrain-mapping mode.

However, unfamiliarity, mindset and the time of day are ever-present threats, perhaps some of these played a part.

Whether it was the intent or not, the track towards the location of Blackrock was established early in the flight. Then at about the correct distance for an ARA, an offset is followed by a further turn to the right for what looks like a go around.

The trace shows that the aircraft continues for some 3 nm and turns left roughly parallel to the GA track but slowly turning more easterly. At approx. 2nm away it turns towards the landing site at Blackrock but with what intent?

The track as depicted does not suggest to me that this was a westerly let down for an approach to Blacksod. If it was, then perhaps the plan changed when the aircraft made for Blackrock after the turn left onto a southeasterly heading. With no altitude data to assist, the picture is particularly unclear.

During the approach and go around there would be good reason to have had the radar on for the entire time, if not in WXR mode then in GMAP. It would be usual to optimize the WXR display with gain and tilt adjustments. With WXR or GMAP modes selected and even Terrain display, there should have been ample overview available unless marred by some significant malfunction.

Regarding the unattributed call of landing at Blacksod. I understand it was given at around the apex of the turn. Other than to overcome possible challenges with comms at low altitude, wasn’t it a tad early with well over 5 minutes flight time to go to Blacksod or was it a part of a clipped call made under duress with a slip of the tongue regards location?

Only time will tell.

Birmingham - it was the same unit a few days earlier but that doesn't mean it was the same crew.

it seems reasonably clear that the aircraft went into the water rather than the rock since Dara survived the crash, suggesting an impact that allowed her to escape but caused bad enough injuries for her not to survive subsequently. The other crew members may still be in the wreckage having been incapacitated by the impact. If they had hit land, there would be a lot of wreckage available and no survivors.

Loquatious - not unusual t get tha call out early so it doesn't distract from the letdown process.