R116 Accident AAIU report discussions

Read the quoted text from the report that I posted again. It says that errors were made and some were trapped and some weren't. You might have a flawed understanding of this kind of investigation. There are always multiple reasons why an accident happens. There is ample evidence here for a degree of fatigue and that may be a contributing factor. It's not going to be black and white like "decision x was made due to fatigue and as a direct result the accident occurred".

All we can say is that they were almost certainly tired and they absolutely made some errors during the flight. If they had been better rested would they have considered the EGPWS warning they got shortly before the accident more carefully? Would they have reacted quicker to the Winchman telling them to come right because there was an island straight ahead? We can't say for certain but in these accidents it's little things that make big differences and the AAIU considered the fatigue aspect important enough to issue recommendations to the operator about how they analise and manage fatigue.

I have not yet read full report, however I am familiar with blacksod helipad and the flight route from BlackRock.

Firstly it seems strange if they were heading from Dublin to Blacksod that they would need to go out to Blackrock to come back in. It maybe have been the wind direction as choppers land into the wind, and don't like to fly backwards or turn direction at last minute. Assuming landing from North West to Blacksod was the best route, then the minimum altitude should have been clearly stated and pre-programmed. Minimum altitude is critical to help avoid all objects, and it seems the minimum altitude was not defined. Naturally the minimum altitude will drop as you get closer to landing and typically you want to land in a direction that is clear of any obstacles, but also into the wind. 200ft seems very low, but there may have been cloud or cross winds at higher altitudes. It may also have made seeing the landing lights in Blacksod easier. You don't want to fly through cloud or fog if you can avoid it and a visual landing is much easier than an instrument landing at a site you are not familiar with and Blacksod is a small pad, surrounded by walls and buildings. 200ft was too low to start, as we know now. The lighthouse light on BlackRock was downgraded years ago to be solar powered, and it's intended for shipping in non fog, so unlikely they could have used it or seen it in bad weather.

In terms of sat Nav, terrain warning etc, as said it often does not have details at very low levels. They are not designed for search and rescue 200ft flights, they are often designed for light aircraft which maintain high minimum heights except when about to land at a proper airport which typically would not have obstructions. Another issue may be memory card capacity. Some of these systems may be a 30 year old design, aircraft certified and may not have gigabytes of memory. They physically cannot store every high point above 200ft on the earth. Maps may be limited to UK/irl or Europe only, and may only reliably include things above 500ft. When you go below 500ft you take your chances.

In terms of time to turn the chopper, remember choppers move very fast, a "back seat driver" mentions something over internal Comms, they discuss it and what it means, they don't realise the distance away and the urgency, they start to turn, but fractionally too late. You need to confirm direction changes, you don't want to turn towards the obstruction.

I really think the whole navigation system is of very limited use below 500ft, I think the minimum altitude should have been tied into waypoints, and used in an idiot proof way. It sounds like these semi official refuelling sites like blacksod are not as well structured or documented compared to proper airports.

I don't really understand the big benefits of top cover. If it's just to relay radio comms, I would have thought a satellite telephone would be reliable and better than relaying messages over radios. If it's to have another chopper in the area, fully fuelled to take over or support main chopper down, I can understand.

My heart goes out to all involved. I suspect similar SAR in other countries have similar problems at low level flights. I know this job is dangerous, from getting knotted up into fishing boats, but really this event could have been avoided.

Read the report. The warning was not ignored, there was a delay from warning to turning, while direction was confirmed

I would expect the report to say what errors were made by the crew if any and how they formed part of the outcome, and for them to appear in the conclusions. I don't see anything in the report that identifies a faulty decision made by the crew (beyond vague trapped and unstrapped errors) at that all played a part, let alone one that was the result of fatigue.

All the report says was "mistakes were made". That doesn't help anyone if they cannot identify them and what role they had.

But perhaps I might expect too much from the report.

I haven't read it all though, so maybe it does have those answers within it.

No. It's clear from the transcript that avoiding action was taken based on the warning from the rear crew member. The heading had been changed but, given the closing speed and size of the obstacle there was not sufficient time to avoid the collision.

Without wishing to draw out the point, an island of approx 400m x 300m should have what, maybe at least 10 elevation points measured on it with a random 90m grid. Looking at photos of this island, even if no data point was near the actual summit, it looks like the adjacent ones would have been recording 50-60m above sea level at least. I think the problem is probably that the data was recorded by the Russian or NASA satellites/ shuttle but excluded from the final data as too far offshore. Hasn't the Pacific many small islands, possible that many of these are excluded too to save space. After all 2/3rds of the earth is water which is theoretically level, so no point in using up large amounts of memory with blank data. I think this is how these things work but who knows, maybe the American, Russian and Chinese military have access to full datasets for their own purposes. And just release edited versions for other use, bit like the selective availability or whatever it was called for GPS signals a while back.

This is a dump of the raw data at the location of Blackrock island.

I have seen other anomalies with this data where measurements on very steep sided mountains or near vertical cliffs have crazy values. Maybe the radar waves were bounced off at an angle and caused the errors, I don't know. There's a vertical error of no more than 16m inherent in the way the measurements were taken also.

When the SRTM data was being gathered, the US was scanned at a higher resolution (30m), but even that data is publicly accessible and not restricted in any way.

Seems like it's a preprogrammed SOP

You can check the transcript of the voice recording. It's in the interim report. I presume it's in the final report as well. The description above is accurate and it's not blaming the pilot or the winchman, because neither of them knew they were approaching a 280 foot rock at that point.

The rte report https://www.rte.ie/news/ireland/2021/1105/1258054-r116-report/ says they were travelling at a ground speed of 90knots. That's just over 166kmh.

"The investigation concluded that the first indication the crew had about the obstacle in their path was when Winchman Smith announced he had detected an island on the infra red camera, when the helicopter was about 0.3 nautical miles (550 metres) from it, travelling at a ground speed of 90 knots."

I think you might be missing my point. This wasn't a general comment by the aaiu, it was in the contributing factors for the accident. I fully agree with you that tiredness can impact performance negatively and severely. That is well established and I fully accept that.

The issue is that in the contributing factors in the report, no decision, action or lack of action that the crew took is identified that one could reasonably say that was a result of tiredness. In fact, none of the crew decision making really appears in the contributory factors.

The fact they were tired is worth noting of course, but is somewhat irrelevant if no decisions they took, let alone ones they took due to tiredness are contributing factors to the accident. If a driver is hit by an asteroid on the way home, is the fact that he's tired relevant? If the report is saying they crashed because cloud was low and the obstacle was unmarked on their nav system, not because their reaction times were low, or there was a loss of situational awareness or similar, is tiredness really a factor?