Well said AAKEE!

Unfortunately 10 nm scale is not that perfect to detect obstacles within range 1,3-0,6 NM.

S76 Heavy, couldn't agree more.....Radar!!!!!!

There are many holes in this piece of cheese that have been discussed....They all played a part, However, simplifying the situation, whether Blackrock was in/not in the database, an Imc letdown, a vmc night letdown etc etc...I don't care what the situation was, really the bottom line comes down to using the radar.. This IS your primary piece of Equipment that will save the day...When I used to fly offshore, even night VMC letdowns into the blackness, play with the radar, use the different modes, tilt, adjust, re-adjust, check all clear ahead, start the letdown...during the whole procedure, in any turn, the level off, I'd still be adjusting the tilt, etc, re-look where you are going, keep the communications going, and if the other pilot told me there was now a return , even if I was expecting something there, I wouldn't assume it was x until I could clearly see it, and if not visible, climb or turn well away until visual, etc.. and even though I am PF, I'll now take a glance too, see what's ahead, work together as a crew, not just take his/her word for it...and adjust accordingly...etc...I have used FLIR but we didn't have that offshore, didn't have other crew members apart from the other pilot, the rigs were in the gps but tankers passing through were not, doesn't matter, use the radar...don't need flir, gps doesn't show every possible target...doesn't matter, use the radar....and if I was x miles away from my destination and I was told to come left/right, alarm bells would have gone off?? Why come left or right? what the hell is out there? I am gobsmacked at the lack of use/poor comms from the radar operator and almost blasé attitude from the P1? If you were unfamiliar with an area too I would have been even extra cautious...used properly, at some point in the turn a large blob on the radar screen would have caught your attention even if it was off the screen on the last known approach track which has been suggested here due to drift!. It is easy in Hindsight to criticise, but as professionals, I am amazed and saddened at the total waste of life of 4 crew members, who I have the utmost respect for going out day and night to save others....
SAR is different from offshore, letting down towards land/rocks is different to letting down towards rigs, I have done both, but, the RADAR was still the primary tool to stop you hitting something....

RIP all the crew members, and I wish all the family members find the strength to get through this difficult time......

Agreed.

---------------

Brutal wrote:

Long time since I did an ARA, but isn't the SOP to have the radar at 2.5nm?

What will be interesting is how the operators deal with the crew issues which have been noted and will inevitably form part of the final report.

Will the operators and regulators hide the shortcomings in equipment and procedures behind any failures of the crew to monitor the radar and conduct the letdown correctly?

We are often told about 'just-culture' in Safety Management Systems but how will that stand up to pressure from the operator to avoid and blame/litigation?

Sounds like ALT a great friend and mentor... 😢

The thing which is hardest to explain here is that we know the copilot looked at the radar screen about 30s before impact and called a small radar return at 6nm/11 o'clock. At this point he was just under 1nm from Blackrock, so what happened to the Blackrock return ?

Assuming the radar return was Duvillaun More then it's about 0.5nm across from the radar's perspective. At 6nm the circumference around the aircraft is about 36nm (6nm*2pi). Let's say the radar sweeps out 60 degrees of that, ie. 1/6th of the circumference or a 6nm arc. It follows that Duvillaun More would have a lateral extent of 8% (0.5/6) of the sweep.

Run the same calculations for Blackrock which presents a lateral extent of about .12nm at about 1nm range and it turns out that it would occupy a similar amount of the sweep. Given the heading and drift of the aircraft those returns might well have been adjacent on the sweep although very different distances away.

It has also been suggested that Duvillaun More and Blackrock would have painted very different pictures on the screen because of the different topography and distances involved. I'm thinking Duvillaun More may have been more of a blob, but Blackrock has some 'stealth' features, sharp edges and flat surfaces angled away from the radar. In addition there might have been some clutter on the screen which might still include some weather in the solid IMC above even though the radar was in ground mapping mode.

I'd love to know from a SAR driver with lots of experience of interpreting weather radar pictures using the fit in this aircraft to speculate on what the radar picture might actually have been. Somehow the Blackrock return was misinterpreted but how ? Would the Carrick Islands just in front of them have appeared on the screen and lulled them into believing that the Blackrock return was a similar low feature ? Could Blackrock have looked like sea clutter or weather somehow ? Could Blackrock itself have created a local weather effect that masked the island ?

It's a sad fact of life that if a fully serviceable aeroplane flies into something it's not the aeroplane's fault.

Its an interesting point Punto. I am not SAR but a few ARAs in the past. I generally aimed the RADAR slightly below the horizon, maybe 3 degrees nose down, turned the gain to full, always in WX mode, and then backed off the gain to remove the sea clutter, leaving (what I believed) to be the hard bits behind.

I recall most people I flew with did mostly the same procedure. Although an handful would obsess about which mode they wanted. I think "Search" modes featured a lot in these discussions, but if in Command, I always resolutely insisted on the WX mode and the technique I have described.

Having written this, and now as we review this accident, it seems bizarre that we have not formally mandated an exact technique for setting the RADAR up. (Maybe in some other organisations they have).

Anyone have any other techniques they would like to share or has anyone been subjected to a "Mandatory" setup.

In fact I change my story a bit having thought about it. What I did was never relied on the angle of dangle indication. I would turn the gain full up, turn the head down until I had total sea clutter, or in calm, targets crystal clear where I expected them to be. Then I backed off the gain until the sea just about disappeared. Funny what comes back when you read what you wrote previously. Nope, I never used the angle of dangle thingy.

There could be some cognitive issues here regarding what the crew were seeing versus what they were expecting to see.

If I was running the investigation I would be insisting on an S92 flying the same profile (day VMC) in the same configuration to have a look at the indications prior to the point of impact. Obviously you can't replicate the weather conditions so the radar returns would be a variable but it would be a very useful exercise.

It's Ireland. It's very easy to replicate the weather conditions.

Less facetiously, I think that is a great idea. I wonder if with the sharp vertical extent and it's proximity, and it's stealthy qualities, Blackrock looked very similar at 1nm to the Carrick Islands at this point .2/3nm away. If the crew could rationalise away the Carrick Islands, then it would be easy to do the same for Blackrock.

On the CVR it has the co-pilot reporting a contact at 11 o'clock, 6 miles at 32secs or about 0.75 n.m. before impact. Drumacappel wasn't at six miles then; it started at about 5 miles. What was at six miles was the highest point of the island on the eastern side. A radar tilted at 0 degrees would have seen the coast, one titled up wouldn't.

From personal experience with marine radar, the images generated with a range scale set to three miles or less are pretty useless due to sea clutter. Also at these ranges there is the possibilty of very strong radar returns activating protective devices that are designed to prevent radar transmitter energy from destroying the very sensitive receiver section. In effect, the more powerful the radar return, the more likely that the receiver will be desensitised and effectively nothing will be displayed on the screen.

This is a very simplistic explanation of why they maybe saw nothing on the radar screen, as there are numerous settings that all interact and affect the radar picture. Depending on the wavelength of the radar, cloud and rain reflections can also absorb or reflect sufficient energy to blind the radar receiver at close ranges.

I had several years mucking about with the marine stuff including installations and commissioning, if anyone feels the need to argue or debate the details via PM.

not my league but were they Night VMC at 200 ft and did not see from afar the light on Blackrock flashing? Was the light house working 100%?

It's likely the light was in cloud.

And that the 'heads-in' mindset along with the likelihood they didn't even realise there was a lighthouse there meant they weren't looking for it.

Sorry SAS - I don't understand your post - yes times change, in this unfortunate crew's case for the worse. Over complication of navaids in an overworked cockpit, a procedure mistakenly flown because it wasn't an IFR plate, unreliable data inputs to the nav kit, rear crew not totally involved in the procedure (poor CRM) - all or any of these things may have contributed to the cfit. Mr Eacott referred to an early RN SK (not a 61) cfit - I assume RN procedures changed post that crash and the RAF procedures followed, and in time incorporated GPS and NVD's. Tragic accident to an experienced crew that shouldn't have occurred and yes, I've been to Blacksod on a few occasions too.

And if they weren't looking for it, it is possible they weren't monitoring the other sources of information to look for it either. I didn't see if the report has details on the radar range settings. Can the radar range be set separately from the display range?

Does anyone know what sensor configuration the EO/IR turret has? Is the aircraft capable of displaying two video outputs at once?

Any helicopter weather radar I have used (excluding that fitted to civilian AW machines) have been good down to half a mile for obstacle avoidance as long as it is in the correct mode. It's no good leaving it in wx mode because the gain is then fixed and non adjustable in order to optimise the observance of Level 3 weather returns which equate to an active thunderstorm (or very heavy rain).

In absolute contradiction of Double Bogey above, use of the correct Search mode is vital. There will be at least one which is optimisied for short range selection which will reduce the pulse length and increase the pulse frequency. When level at 200' or thereabouts, tilt control should be set about level which will give about +/- 3 to 5 degrees of scan above and below the horizontal depending on the diameter of the aerial. The larger the aerial, the narrower the beam will be in both horizontal and vertical plane. If the radar is set correctly, Black Rock should have been painting loud and clear.

DB

You might want to check your memory as the gain function does not work in weather mode. The important point about using search 1 or 2 modes when looking for a rig or ship is that it is short range (20nms or less) and the PRF is increased. To put it simply, higher PRFs transmit more energy in a given time, which produces stronger and more defined radar reflections. The best picture will be provided by a combination of search modes, tilt and appropriate gain setting.

Ex Marina, you could be right. It's a few years since I used the radar in anger but I was pretty sure that how I managed it. The Search functions in my experience are too complex, probably for the reasons you describe and I do remember a few times realising we had no return on a target that was definitely there and realising the copilot had selected a search mode. A quick switch to WX mode and sudenly the target is a nice big red blob.

In my experience a TSO compliant radar will not allow the operator to change gain in weather mode.

sorry gents, but maybe everyone who uses the radar offshore/sar should do some reading, my goodness!!!!!

Primus 660 radar

The GAIN knob is a single–turn rotary control and push/pull switch that is used to control the receiver gain. Push in on the GAIN switch to enter the system into the preset calibrated gain mode. Calibrated gain is the normal mode and is used for weather avoidance. In calibrated gain, the rotary portion of the GAIN control does nothing. In calibrated gain, the color bar legend is labeled 1,2,3,4 in WX mode or 1,2,3 in GMAP mode.
Pull out on the GAIN switch to enter the system into the variable gain mode with VAR (variance) displayed in the color bar. Variable gain is useful for additional weather analysis and for ground mapping. In WX mode, variable gain can increase receiver sensitivity over the calibrated level to show very weak targets or it can be reduced below the calibrated level to eliminate weak returns.
WARNING
HAZARDOUS TARGETS CAN BE ELIMINATED FROM THE DIS- PLAY WITH LOW SETTINGS OF VARIABLE GAIN.

:{

Maybe this crew were as familiar as some here with the equipment they were using then it's no wonder accidents happen..(I am not saying they were, but some of the answers here from professionals who use wx radar is shockingly scary)!!!:sad:

Round,


"Level" to what would be the Horizon and compensating for Aircraft Pitch Attitude variation of what would otherwise be Wings Level in Pitch due to the speed it is flying? Is that the "Level" to which you refer?

Brutal, thank you for confirming my actions. However your adminoishments also apply to me because I learned the Radar procedure a long while back and really just kept applying it to each new box we were equipped with.

Like I said for me the simpler the better. Start with max gain WX mode point at the sea and trim the radar up until the picture is clearer and reduce the gain to remove sea clutter. Served me well but maybe I should have read the books a little more.

All references to 'search' modes (SR1 or 2) denote Puma pilots and are not relevant to the Honeywell Primus 701 used in the S92. No such modes there :p. (Ok, unless you think of 'ground mapping' modes as the same. Don't shoot! ;) )

The 701A is gyrostab:ed up to 30 degree of combined nose up/down/bank angle.
The tilt value is refering to the horizon( info from IRS i think).

Depending on antenna, a wild guess of size the radar lobe on the S92 is somewhere around 8 degrees... wich means it will see 4 degrees up and down with zero tilt. Thats the zone of 'good returns', it will see and plot up to total of 14 degrees but not with the "calibrated" gain.
Rules of thumb for radar is one degree at one mile(Nm) makes 100 foot. So at 200 foot with zero tilt it should have sen ground(the sea level) as close as 0,5 mile in front.

I think most offshore/SAR people knows how to tune a radar.

You could start by refering to manuals for a search and rescue/ weather radar.

In some purpose, they dont do exactly the same thing. For wx, yes but...

Can any S92 operators tell me the size/colour of FMS WP symbols? Are they overlayed on top of the radar video?

What a generous series of posts DB. And your original observation is very insightful. How could there not be an SOP for something this crucial. Let's hope there was here, and let's hope it's published in the final report.

Looks like roundwego is doing some research into the consequences of the Primus using the GMAP2 setting with 10nm range, so let's hope something good comes of that. It's suggestive that these settings are specifically referred to in the report as increasing the amount of clutter on the screen, and it was a high seastate night.

Would still love to know from users of this sort of kit what a rocky outcrop looks like on radar vs a distant headland. All the radar energy from any point in the scan's azimuth will come back from a very narrow range which the screen ought to interpret as a rough coastline rather than as a blob. And there should be nothing at all behind the coastline as it's in radar shadow. I think someone else was talking about this earlier.

Very hard to see how you could miss a feature like that and yet spot a generic blob at 6nm. But as they weren't expecting a rock, maybe they just tuned out or rationalised the echo as something unthreatening.

Brutal,

That might be the case on the Primus 660 but not the Telephonics RDR 1500B/1600/1700A systems. IIRC the L2 and 225 were fitted with RDR 1600 as standard in the UK so in Wx mode the receiver gain is preset and cannot be changed by the pilot. That is why I suggested a memory check for DB as I know he flew those types.

Shockingly scary? Perhaps not - it depends on your kit!

In Primus 701A the gain can be adjusted also in Wx mode. It can also easily be reset to calculated( fixed gain) to get the appropriate WX readings with correct colors. When used in Wx Alert mode the gain is fixed and cannot be changed.
If the above apply to S92 due to implementation etc, I do not know.

Thank you ex-machina, I cannot remember ever using a wx radar where the gain could not be adjusted in wx mode....maybe I have been flying too long??

AAKEE
"I think most offshore/SAR people knows how to tune a radar".

Sorry to inform you that many times I have witnessed, especially during checks pilots not properly using the radar...ARA overhead, in the descent I noticed a return that would be on our inbound track, we levelled off, turned to face the inbound track and had already reduced speed, then proceeded with the descent, with the tilt only just giving us a return at six miles, but not the previous target...when the P1 was questioned he hadn't noticed the return outbound and hadn't bothered to re-adjust the tilt to look for potential returns closer, and not understood that the reduction in airspeed made the nose pitch up slightly more, and lose the first return...very very simple errors, but potentially lethal....again, my post was not on specific radar types, but pilots failing to use/utilise/understand radar and it's pitfalls.

DB, I remember being taught that way too, full gain to start, adjust tilt, etc...:ok:

What was the CHC In-Service training routine for ICG Pilots and Crew?

Many years ago as UK SAR was being shifted to the Civvie side from the Military....Crab and others raised concerns that then existing Training Hours and array of Training Tasks might decline.

Anyone able to share their knowledge about ICG training?

10 mile scale
 

For the comments on the 10nm scale, I dont se a big problem using 10mile scale.
This scale still shows everyrhing, scaled down though.

For a let down to hover( transition down) we use a fixed scale, more zoomed in than 10 nm. But then you do this close to something, and need to see this more in detail. I think there also a good thing to use a standard setting making you refer to the picture at a 'known' scale.

For a descent to below clouds and the plan to continue flying I think the idea to see radar returns that give you SA in the radar picture, for example the shore line or islands is good, that may be the reason for that selection. Too zoomed in and you loose the SA and the easy relation to a map/moving map and so on.
(I would have worked with radar settings, and scale to make sure but thats not the point here).

The wx mode of the S92 radar IS gain adjustable.

Something the size of Blackrock could not be missed whether in WX or GMAP. Quite a large return would be bright red on the screen, whether on a 10mile scale or smaller. Even if the gain was badly set there is still a noticeable difference in return colour. At 200' the tilt would have to be greater than +5 to start shrinking the contact.

LZ

I've been lurking here for the past few weeks since the tragic accident and haven't posted. However I have a question that is troubling me and would be grateful for any clarification that can be provided by y'all. I have read the AAIU report, and have looked at a number of Coast Guard related information resources that are available on the web.

My reading suggests that the IRCG ought never to have been tasked to deal with the SAR/Medevac incident in the first place. According to the AAIU report, "The position of the FV at the time of the call was N 54 17.450’, W 014 06.944’, which was 141 nm and bearing 270 degrees from Eagle Island, Co. Mayo. "

The North Westerly boundary of the Irish SAR responsibility is contained in the IRCG SAR framework, previously linked to here and available at http://www.dttas.ie/sites/default/fi...-framework.pdf

The Irish SAR 'box' is contained within the area identified by the coordinates laid out in Appendix 1.1 of that framework. These coordinates are listed as:

55 20N 006 55W - 55 25N 007 20W
55 20N 008 15W - 54 45N 009 00W
54 34N 010 00W - 54 00N 015 00W
51 00N 015 00W - 51 00N 008 00W
52 20N 005 30W - 53 55N 005 30W
54 25N 008 10W - 55 22N 006 55W

A depiction of that area is contained at Image 1 attached to this post.

Anything outside the Irish box lies with the designated UK SAR area, to be dealt with by UK-based SAR rather than Irish SAR. and is depicted on Image 2, which is taken from Annex 1 of the Strategic Overview of UK's SAR Operations published in January of this year.

Finally, Image 3 depicts my placing of the published coordinates of the North Westerly extremity of the "Irish SAR box", coupled with the coordinates of the FV published by the AAIU.

My question is this: Have I totally made a hames of placing the published coordinates onto my Google Maps?

Or,

Did that FV makes its call within the UK realm of responsibility, rather than that of the IRCG? If so, when the FV contacted Malin on that night, why did Malin start the whole process of tasking Irish SAR resources when the FV did not lie within its area of responsibility. Why did Malin not hand off to the UK- based SAR services instead?

The radar transmitter is pumping out pulses of energy of up to 1,000 watts. The receiver is designed to respond to returning echo signals measured in micro watts, a millionth of a watt. Even if the transmit/receive protection circuits work in around a microsecond, you will see nothing within a 300 metre range. If they take three microseconds to switch over, you are blind to everything within a kilometre. We are talking millionths of a second here to switch from 1000 watts out to a few millionths of a watt coming back! The technology is well proven, but transmit/receive delays increase as equipment ages, so close in blind spots get bigger. A crew may actually perceive the radar equipment as working better as it ages because of an apparent reduction in close in sea clutter.

As stated earlier, very strong local reflections can overwhelm the receiver protection circuits and render the radar blind even at longer ranges. It is possible to tune the radar to reduce transmitter power, reduce or tune out sea clutter, reduce receiver sensitivity, and digitally enhance the display picture, but this takes time and a certain degree of skill to optimise the settings.

Judging from the cockpit transcripts, I am pretty certain that the radar did not display Black Rock in any recognisable form due to the weather conditions at the time, incorrect mode or adjustment of the radar receiver, slow changeover of the transmit/receive protection devices, or possibly overload of the receiver circuits due to very high return signal levels. None of these scenarios would necessarily be apparent or present any real problems to the crew over open water looking for a vessel, particularly at longer range settings.

If Black Rock wasn't showing on the radar display, then the scepticism voiced by the pilot and delay in changing course, in response to the warning from the FLIR operator, makes perfect sense.

radar ground mapping
 

I'm trying to inform myself of wx radar and its ground mapping mode, how it works, what it might look like etc.

I found the following old video helpful and in particular the part at 33:55 time linked below:

https://youtu.be/O4UxlOBvTkI?t=1975

and the attached image seems to show the red crescent shape of a mountain and its shadow into the "ground stripe"

That works out Pruneface. Double-checked the AAIU report and the Irish SAR Framework and put the numbers in Google Earth and it works out about 11nm into the UK SRR.