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Missing Twin Squirrel: Wales/Ireland

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Missing Twin Squirrel: Wales/Ireland

Old 1st Apr 2017, 10:37
  #181 (permalink)  
 
Join Date: Apr 2017
Location: Welshpool
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Originally Posted by Capvermell View Post
I think this lower level of magnification at Streetmap.co.uk - Map of 52.840320, -3.993511 shows rather better where the site actually is in relation to the coast and the height of the actual mountain/ridge crashed in to.

It would also be interesting to know what altitude they were travelling at during most of the rest of the journey from Luton and what effort they made to fly higher when flying over terrain chock full with mountains as high as 1085m.

If determined to make the trip in such adverse weather conditions its also hard to see why they wouldn't have flown over lower terrain and north of but close to the North Wales coast, although even then there is a long and dangerous ridge of mountains up to 1064m high just south of Llanfairfechan. But as the Twin Squirrell is capable of flying at up to 3,400m was there any good reason for them to be flying this low in this area. Of course I expect weather and lack of visibility at higher altitudes no doubt came in to the equation. Or was lack of fuel to take a more circuitous route with this amount of adult passengers and luggage also potentially a factor?
On the first day of the search operation, cloud cover was down to 300m or so. Visibility was said to be around 10 feet.
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Old 1st Apr 2017, 12:03
  #182 (permalink)  
 
Join Date: Jun 2009
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Sad that on a 'professional' forum the pilot is being blamed for flying too low in poor visibility, with little evidence. He may have been 1000 feet above the highest mountain and experienced a catastrophic mechanical fault or taken ill. It's no so long ago that the entire rotor came off of a helicopter. Had they been in poor visibility and the wreckage not found would the same presumptions have been posted?
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Old 1st Apr 2017, 12:05
  #183 (permalink)  
 
Join Date: Dec 2007
Location: UK
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Originally Posted by SandyYoung View Post
Sad that on a 'professional' forum the pilot is being blamed for flying too low in poor visibility, with little evidence. He may have been 1000 feet above the highest mountain and experienced a catastrophic mechanical fault or taken ill. It's no so long ago that the entire rotor came off of a helicopter. Had they been in poor visibility and the wreckage not found would the same presumptions have been posted?
No because they weren't over high ground and in an MCC full IFR machine.
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Old 1st Apr 2017, 12:28
  #184 (permalink)  
 
Join Date: Oct 1999
Location: UK
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Great post, justanotherflyer. I call it 'setting expectations' and it applies to situations outside aviation as well. Your description:

" Once airborne, the pressure to keep going just that further mile, to look for the gap in the cloud or the lifting in visibility, can then become intense, for fear of disappointing the companions on board. We've all been there."

Is exactly what I meant by that 'land' decision being a difficult one, and the temptation to 'press on pressing on' is very strong.
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Old 1st Apr 2017, 12:28
  #185 (permalink)  
 
Join Date: May 2010
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Originally Posted by SandyYoung View Post
He may have been 1000 feet above the highest mountain and experienced a catastrophic mechanical fault or taken ill.
That may well be the case. However, Information regarding the circumstances and looking at past incidents in similar circumstances tells us that the probability of this being due to catastrophic mechanical failure is very, very low (realistically <5%). The fact that it hit barely underneath the summit of that ridge also points in a clear direction.
Professional Pilots stated that they would consider this flight on this route, weather and time of the day challenging even in a much better equipped bigger Helicopter and this coming from Military / SAR Pilots gives me a clear idea what that means for a PPL in a rather small helicopter with limited equipment to deal with such an environment.
Chances are 1 + 1 = 2.
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Old 1st Apr 2017, 12:40
  #186 (permalink)  
 
Join Date: Jun 2001
Location: UK
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MSA is the minimum altitude to fly at when flying IFR. From a legal point of view one has to comply with the Minimum Height Rule which is 1,000 ft above the highest point within 5 nm of the aircraft. (With certain specific exceptions). Flying IFR assumes the aircraft is suitably equipped and the pilot has the appropriate instrument qualification. Also operators might specify higher criteria that the Min Ht Rule in their manuals for a variety of reasons. You also have to ask how accurately you can pinpoint position. To allow for errors you might look 10 miles either side of track (and beyond track) to find the highest point on that leg of the route.

Flying VFR you may fly below MSA. However it's a good idea to calculate a minimum VFR altitude. The idea behind this is to have a preplanned "If I can't maintain this altitude then I'm turning back or diverting". You would also use this figure before flight when studying the Met F215 etc to make a go/no go decision or electing to fly a different route clear of higher terrain.

This hopefully prevents pilots from ploughing into bad weather and then carrying on until they create a problem for themselves. To arrive at the Min VFR Alt look at terrain and obstacles en route and then ask yourself "How low do I want to be to the ground?". This figure may well vary depending upon the individual pilot's experience. Ask yourself "Do I really want to be flying below 1,500 - 2,000 feet above ground level?"

All the above is notwithstanding the low flying regs with respect to congested areas etc.

NB As has been stated previously we don't know the cause of this accident and my comments are not intended to pre judge the results of the investigation.
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Old 1st Apr 2017, 13:49
  #187 (permalink)  
 
Join Date: Apr 2000
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Trouble is, it's far too easy to look at the clouds on the top of the hills and then get funneled down the valleys where you can still see and maintain your 500' agl - right up to the point where the valley floor is gradually climbing and you turn a corner into a dead-end (sometimes sadly, literally) with no escape route except a turnback towards the high ground of the valley sides.
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Old 1st Apr 2017, 13:53
  #188 (permalink)  
 
Join Date: Apr 2000
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He may have been 1000 feet above the highest mountain and experienced a catastrophic mechanical fault or taken ill.
It is a possibility but, as already mentioned, a very remote one.

Without a CVFDR, there will only be the radar trace and any information that can be gleaned from the electronics on board - GPS, ipads, mobile phones etc.
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Old 1st Apr 2017, 13:56
  #189 (permalink)  
 
Join Date: May 2003
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Originally Posted by N-Jacko View Post
Which is, even by the standard of PPRuNe, potentially misleading.
N-Jacko, thanks you are correct, of course it's not MSA. I'll have to blame the late night hours for that one.

Really what I was referring to is the concept of "safety altitude" as calculated by VFR flyers for x-country navigation. I have amended my post in view of your valuable correction.

BTW I am not making assumptions about the contributing factors in this particular accident, which have yet to be determined.

Typically safety altitude might be deemed as 1000 feet over the highest en-route elevation (or 2000 feet over hilly terrain).

My point is that when I have queried more than one student or pilot over the years about what that idea means, the response has been in effect "don't go any lower than safety altitude if in bad visibility". More or less taking it as akin to the IFR concepts of MSA or MORA. That way of thinking is sure to lead to hazard.

What I emphasise to students is that safety altitude is the minimum height above terrain that offers some sort of useful margin of choice for visual manouvering should wx deteriorate. If cloud or reducing vis. force you down to your calculated safety altitude, then for the sensible pilot there is no choice but to change course, you simply can't proceed.

Occasionally I've kept mum and let a student keep going a bit further to see what happens. It's not a pretty sight as the wheel gets gripped tighter and the pilot leans forward in the seat straining to see what's coming, while the altimeter inches downwards. Accidental flight into IMC becomes a real possibility. One chap was thrilled to see blue skies in a distant gap and flew right into a wide deep valley ahead. Moments later we were boxed in visually. It took my changing to IFR and flying out on top to get us home - flying by himself a difficult precautionary landing would have been necessary. The guy was sweating bullets, and vowed "never again!" a dozen times.

Anyway in summary a proper understanding of safety altitude, plus a resolute automatic decision to alter course towards clearer skies if you can't maintain VFR above it, are essential parts of a safe VFR mindset.

addendum: folks, kindly note I am writing from a FW perspective. I appreciate this is a rotary forum.

Last edited by justanotherflyer; 1st Apr 2017 at 14:20. Reason: addendum
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Old 1st Apr 2017, 14:04
  #190 (permalink)  
 
Join Date: May 2003
Location: Cote d'Azur
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Originally Posted by Non-PC Plod View Post
juustanotherflyer,

I like your "pre disappointment" approach. Do you mind if I blag it and your spiel to use in TEM training?
Please, be my guest. I use it for the very same purpose myself.
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Old 1st Apr 2017, 14:10
  #191 (permalink)  
 
Join Date: Nov 2004
Location: Western Oz
Posts: 51
Are we still talking about helicopters

2000ft above hilly terrain for a VFR helicopter?
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Old 1st Apr 2017, 14:14
  #192 (permalink)  
 
Join Date: May 2003
Location: Cote d'Azur
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Originally Posted by PhilJ View Post
2000ft above hilly terrain for a VFR helicopter?
Hi PhilJ,

As noted in my original post, my background is in FW flying. If helicopter practices are typically different, then please adjust accordingly.
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Old 1st Apr 2017, 14:47
  #193 (permalink)  
 
Join Date: Dec 2014
Location: Africa
Posts: 360
Notorious for doing the unexpected?

Originally Posted by configsafenot View Post
The area is notorious for weather closing in on you unexpectedly
I know what you mean, but isn't a bit of a contradiction in terms?

Originally Posted by snchater View Post
I'm a fixed wing pilot (C182) and flew into Caenarfon at the weekend. Despite the cavok conditions I almost got caught out by the rotor in the lee of the Snowdonian range (1000fpm down + very turbulent).
I note from the Valley metars that there was a brisk (20kt+) north-easterly wind on the day of the accident . Do helicopters cope well with turbulent conditions?
G-XLTG
No, not really. Best to be avoided.

Originally Posted by alphanumeric View Post
a thought any ppl who wanted a twin rating needed to pass the cpl exams first?
No, why? Maybe in some countries, but in general, no. But in general I would assume that even private owner/PPL would have accumulated a few hours while working his way up from piston to turbine to twin...
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Old 1st Apr 2017, 17:40
  #194 (permalink)  
 
Join Date: Sep 2011
Location: USA
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Looking at the UK visual flight rules in section 4, outside controlled airspace, how long has this helicopter provision been in effect?

https://www.bfgc.co.uk/VFR_Guide.pdf

For helicopters operating at a speed which, having regard to the visibility, is reasonable:
Clear of cloud and in sight of the surface.
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Old 1st Apr 2017, 19:03
  #195 (permalink)  
 
Join Date: Oct 2004
Location: York
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Looking at the UK visual flight rules in section 4, outside controlled airspace, how long has this helicopter provision been in effect?
At least 4 decades to my certain knowledge. Quite probably more?

This is the fundamental difference between helicopters and fixed wing. It can be, and frequently is, perfectly safe to fly in weather so marginal that ONLY entry into IMC prevents flight in accordance with VFR! Not the case in a fixed wing!!

The underlying principle is that the ONLY back up is an immediate IFR climb above safety altitude, or an immediate landing. If one is unable due icing, or unqualified, to confidently conduct BOTH an IFR climb, and subsequent instrument recovery to a suitable diversion, then ONLY an immediate landing remains!

However, if at the same time, the terrain over which you are flying is not suitable for a landing, then your options have disappeared. Tragically the result is then inevitable.

I say again. I have no idea what the cause of this accident was. It's simply too early to say. Unless there are recorders onboard the aircraft we may never know with any certainty. Investigators may just have to collect what physical evidence there is, and make an informed guess. Very, very sad for those left behind, but a distinctly possible outcome.
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Old 1st Apr 2017, 19:44
  #196 (permalink)  
 
Join Date: Nov 2008
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4468
The underlying principle is that the ONLY back up is an immediate IFR climb above safety altitude, or an immediate landing. If one is unable due icing, or unqualified, to confidently conduct BOTH an IFR climb, and subsequent instrument recovery to a suitable diversion, then ONLY an immediate landing remains.
However, if at the same time, the terrain over which you are flying is not suitable for a landing, then your options have disappeared. Tragically the result is then inevitable.
I don't agree with that, what about flying on, low and slow (30 kts) in sight of the surface until finding somewhere suitable to land?
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Old 1st Apr 2017, 20:23
  #197 (permalink)  
 
Join Date: Nov 2016
Location: Cumbria
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Flight up to MSA. I am not sure if either the pilot was qualified for IFR or if the aircraft was IFR capable, in the event of the weather, there would have been multiple opportunities to land on level playing fields or school grounds from Welshpool, Bala and beyond. Based on the impact on Rhinog Fawr, and the weather, it seems unlikely the aircraft was still under VFR.
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Old 1st Apr 2017, 20:53
  #198 (permalink)  
 
Join Date: Apr 2000
Location: EGDC
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Chopjock - have you tried hovertaxiing in limited visibility, in the pissing rain in the mountains? You are certainly not VFR! if your viz is less than 1000m then you are either in cloud or in fog - take your pick.

The answer is to have turned back earlier or landed when there was an option.
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Old 1st Apr 2017, 21:55
  #199 (permalink)  
 
Join Date: Apr 2017
Location: England
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Spot on Crab................
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Old 1st Apr 2017, 22:16
  #200 (permalink)  
 
Join Date: Apr 2017
Location: Welshpool
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Originally Posted by Homsap View Post
Flight up to MSA. I am not sure if either the pilot was qualified for IFR or if the aircraft was IFR capable, in the event of the weather, there would have been multiple opportunities to land on level playing fields or school grounds from Welshpool, Bala and beyond. Based on the impact on Rhinog Fawr, and the weather, it seems unlikely the aircraft was still under VFR.
This is what I don't understand about this incident. The weather conditions were so bad on Wednesday/Thursday that the initial search operation on foot had to be suspended to prevent injury/death of the mountain rescue team members. If it was that bad on foot on a big and rocky mountain, trying to fly across it blind is puzzling.
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