Chinook Power Line Strike Wales
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I take it the wire seen in the film is the one previously hit but now replaced.
MoN - Glad to hear the cab's back OK. The SI will make for essential reading, but let's give the team time and space to do their job. On a personal level I will be very interested if further low level mitigation is recommended via sensor (unlikely given he costs, though it would be a significant step in reducing the DVE operating risk as well), tablet (possible - especially if it's a PED with zero integration - again…) or, most likely, extra restriction and supervision. Perhaps we could re-brigade those Gazelles from NI to the Sqns for Wires Recce purposes again!!! Reading between the lines, I've probably flown with both you and Crab; you're both professional aviators but now exist in quite different swim lanes. There's a clear desire on Crab's part to prevent the needless loss of airframe or life, but, perhaps, it's from a perspective where the view is somewhat obscured. There, who said I couldn't 'do' fluffy!!!!
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On a personal level I will be very interested if further low level mitigation is recommended
DV
Forgive me; I don't have the perspective (or imperatives) of a flight-crew, but ISTR a few facts from my Chinook Maintainer's course in the '90s:
1. In the event of penetration by a projectile, the Cobra system will fill the fuel tanks with flame-retardent before the projectile can leave an exit wound.
2. The major transmision gearboxes have 3 independent oil systems. In the event of triple-failure, the gearboxes will run dry for an hour.
MoN mentions that, after windshield replacement, the damage to the subject aircraftwas appears to be superficial. Given Vertol's/Boeing's attention to survivability on the rest of the airframe, is it reasonable to consider that it doesn't need wirecutters? Certainly, there might be a tendency for an LOH to get catapulted back 2-counties in the event of a wirestrike, but the mass of a Chinook, with a suitably-resilient cockpit frame, is perhaps a different matter?
1. In the event of penetration by a projectile, the Cobra system will fill the fuel tanks with flame-retardent before the projectile can leave an exit wound.
2. The major transmision gearboxes have 3 independent oil systems. In the event of triple-failure, the gearboxes will run dry for an hour.
MoN mentions that, after windshield replacement, the damage to the subject aircraft
Distant Voice Post 17 :-
Distant Voice Post 123 :-
Keep at it DV. The answer is known and will eventually be revealed (it always is!). Rather reminds me of the Fawlty Towers Round of Drinks running joke :-
A 2013 paper covering the MoD Helicopter Safety Enhancement Programme stated,
There is currently no wire cutter kit developed for the Chinook and there are no known plans to develop one. The cost and timescale associated with introducing this capability suggest that an alternative means of protecting the aircraft against wire strike may be a better option. Assessment of a tablet based moving map capability is underway, which would have details of known wires and obstacles overlaid. The key to this type of system is considered to be an effective means of alerting the aircrew to the presence of wires without them having to spend prolonged periods “eyes-in”.
I hope the ODH found suitable mitigation to cover the wire strike risk when he signed off on the ALARP safety statement.DV
There is currently no wire cutter kit developed for the Chinook and there are no known plans to develop one. The cost and timescale associated with introducing this capability suggest that an alternative means of protecting the aircraft against wire strike may be a better option. Assessment of a tablet based moving map capability is underway, which would have details of known wires and obstacles overlaid. The key to this type of system is considered to be an effective means of alerting the aircrew to the presence of wires without them having to spend prolonged periods “eyes-in”.
I hope the ODH found suitable mitigation to cover the wire strike risk when he signed off on the ALARP safety statement.DV
"On a personal level I will be very interested if further low level mitigation is recommended"
I will be interested to see what mitigation the ODH had in place at the time of the accident, and did it reduce the risk to ALARP.
DV
I will be interested to see what mitigation the ODH had in place at the time of the accident, and did it reduce the risk to ALARP.
DV
Below the Glidepath - not correcting
Some interesting discussion here, but you have to look at the whole picture to assess the risk:
1. There will always be unmarked wires - period. So location systems relying on the position of marked wires will always have a vulnerability. Also when operating low level there shouldn't be too much taking your interest inside the cockpit for any length of time, so the 6 P's are critical for this (see point 4).
2. Helicopters have these really cool things called Pitch Change Links or Rods just below the rotor head. If any wire makes it up the cabin roof to this area you are going to have a really bad day. It doesn't matter how big or heavy the aircraft is, these are an accessible and deadly point of catastrophe. This is why you need cutters or some form of deflection away from this area.
3. The type of wires in this accident (11KVa strung at about 30' or less) cause the majority of wire strikes. The poles are often in the trees, the wires turn green soon after hanging and the distance between poles is irregular depending on the terrain/topography. If you regularly fly low level and don't anticipate or mitigate this hazard, your risk score went up considerably.
4. Before training low level, (when possible) it makes a great deal of sense to do a slow, medium height route recce to clear the hazards before getting your adrenaline fill at 120 Knots and 15 feet.
5. Operationally, you may be on your own in terms of wire and hazard mapping if you are in an distant or unknown area, but on operations we have a higher risk level not necessarily acceptable when training.
Low level flying is an operating environment that demands complete preparation, full attention and situational awareness. Hazard mapping systems don't change any of that and wire cutters will only save your life after you've got it terribly wrong in the first place. I'm fully supportive of both of these measures, but they are fully effective only when, as professional aviators, we have taken all the preventative planning and operating measures we can before descending low level.
1. There will always be unmarked wires - period. So location systems relying on the position of marked wires will always have a vulnerability. Also when operating low level there shouldn't be too much taking your interest inside the cockpit for any length of time, so the 6 P's are critical for this (see point 4).
2. Helicopters have these really cool things called Pitch Change Links or Rods just below the rotor head. If any wire makes it up the cabin roof to this area you are going to have a really bad day. It doesn't matter how big or heavy the aircraft is, these are an accessible and deadly point of catastrophe. This is why you need cutters or some form of deflection away from this area.
3. The type of wires in this accident (11KVa strung at about 30' or less) cause the majority of wire strikes. The poles are often in the trees, the wires turn green soon after hanging and the distance between poles is irregular depending on the terrain/topography. If you regularly fly low level and don't anticipate or mitigate this hazard, your risk score went up considerably.
4. Before training low level, (when possible) it makes a great deal of sense to do a slow, medium height route recce to clear the hazards before getting your adrenaline fill at 120 Knots and 15 feet.
5. Operationally, you may be on your own in terms of wire and hazard mapping if you are in an distant or unknown area, but on operations we have a higher risk level not necessarily acceptable when training.
Low level flying is an operating environment that demands complete preparation, full attention and situational awareness. Hazard mapping systems don't change any of that and wire cutters will only save your life after you've got it terribly wrong in the first place. I'm fully supportive of both of these measures, but they are fully effective only when, as professional aviators, we have taken all the preventative planning and operating measures we can before descending low level.
Systems that tell you where the wires are, only if you have already told them where the wires are, bring the words fireguards and chocolate to mind, especially if you didn't know where they were in the first place. Similarly systems that tell you where the wires are as long as they are live fall into much the same category. Which leaves systems that can tell you where the wires are even if you didn't know where they are, and do so whether live or not. Such systems exist (witness the link in Nutloose's #108) :-
http://www.tc.faa.gov/its/worldpac/techrpt/ar0825.pdf
They have the advantage of working anywhere in the world, using laser beams (which no doubt creates some operational restraints). Nonetheless that would appear to be the best solution. They can be fitted into any low flying aircraft, rotary or otherwise. If we trial off the shelf systems already in use, incorporating them according to the regs, and not double the cost by modifying them to uneconomic levels, isn't that the way to go?
I see that tuc tells us the technology was here back in the 1980's...
http://www.tc.faa.gov/its/worldpac/techrpt/ar0825.pdf
They have the advantage of working anywhere in the world, using laser beams (which no doubt creates some operational restraints). Nonetheless that would appear to be the best solution. They can be fitted into any low flying aircraft, rotary or otherwise. If we trial off the shelf systems already in use, incorporating them according to the regs, and not double the cost by modifying them to uneconomic levels, isn't that the way to go?
I see that tuc tells us the technology was here back in the 1980's...
Chinook fixed - for one trip at least.
Video in 4/4 - just banter !
At 00:15: Young Pilot: "I'm not sure about this - you used 6 whole rolls of bodge tape you say ?"
SNCO: "Yes Sir - it will be fine - it'll do a trip - no problem."
00:24: Pilot: "Hmmmmm - OK then !"
Wg Cdr on left thinks bubble: "Glad he's the one signing for it"
Video in 4/4 - just banter !
At 00:15: Young Pilot: "I'm not sure about this - you used 6 whole rolls of bodge tape you say ?"
SNCO: "Yes Sir - it will be fine - it'll do a trip - no problem."
00:24: Pilot: "Hmmmmm - OK then !"
Wg Cdr on left thinks bubble: "Glad he's the one signing for it"
This is easier and cheaper to put up, requires no cross arms on the poles and is said to have 'reduced visual impact' on the environment - i.e. is harder to see. I'm not sure that this latter feature is such a good thing from the point of view of a passing helo pilot.
There has been a fair amount of discussion about wirestrikes, avoidance and results. I stuffed up many years ago and turned a perfectly serviceable Bell 206L into a cabriolet, but survived to share a few insights.
Essentially I had the inevitable list of contributory causes, but having been distracted from my pre planned stop point on a low level film job, I saw the wires at the last moment and hoicked back on the cyclic to clear a string of three wires along a crossing road. Expecting to then collect them with the tail I checked forward just in time to capture the top wire with the toe of one skid, which pulled us significantly nose down.
So far nose down that I was hanging forward in my straps: time slows down. Full aft cyclic wasn’t helping so there was a conscious decision to pull pitch and try to break the wire, which eventually parted with a massive and grateful “twang” followed by a leap skyward. Unfortunately followed by the tail boom being severed by the blades; full aft cyclic can have that effect.
I must have rolled off the throttle instinctively as we didn’t spin, but after reaching the apogee of our upward leap the ground did come up rather quickly on the way back down and full collective wasn’t slowing us down in the autorotation. Adrenaline is a wonderful thing, giving sufficient strength to snap the collective which then became surplus to requirements.
Luck was with us as on impact the MGB, roof and blades all departed to the left leaving us more or less sitting straight on the ground and able to get out of the wreckage, albeit with some injuries.
The lesson(s) learned?
No matter how good the recce, something can always distract the driver especially when single pilot. In this case a school bus.
Think and act, a quick decision can be life or death. Rolling off the throttle saved us from spinning; the engine was undamaged and put back into service!
Wear the right PPE. I failed to have my helmet on for stupid reasons (not uncommon in civvie flying 35 years ago) and was lucky. I had, however, paid for and certified a strong point for the cameraman’s quick release harness which saved his life. Normal ops for those days was to secure the harness to the seat belt anchor points which weren’t (and aren’t) certified for the lateral pull.
Wire cutters would definitely have prevented the wire from trapping the skid/crosstube. The economics of the day didn’t support them for me but for a military aircraft in the low level environment today it is almost criminal not to protect the crew and aircraft with wire strike protection.
Kudos to the crew and Chinook for a safe landing in this incident
Essentially I had the inevitable list of contributory causes, but having been distracted from my pre planned stop point on a low level film job, I saw the wires at the last moment and hoicked back on the cyclic to clear a string of three wires along a crossing road. Expecting to then collect them with the tail I checked forward just in time to capture the top wire with the toe of one skid, which pulled us significantly nose down.
So far nose down that I was hanging forward in my straps: time slows down. Full aft cyclic wasn’t helping so there was a conscious decision to pull pitch and try to break the wire, which eventually parted with a massive and grateful “twang” followed by a leap skyward. Unfortunately followed by the tail boom being severed by the blades; full aft cyclic can have that effect.
I must have rolled off the throttle instinctively as we didn’t spin, but after reaching the apogee of our upward leap the ground did come up rather quickly on the way back down and full collective wasn’t slowing us down in the autorotation. Adrenaline is a wonderful thing, giving sufficient strength to snap the collective which then became surplus to requirements.
Luck was with us as on impact the MGB, roof and blades all departed to the left leaving us more or less sitting straight on the ground and able to get out of the wreckage, albeit with some injuries.
The lesson(s) learned?
No matter how good the recce, something can always distract the driver especially when single pilot. In this case a school bus.
Think and act, a quick decision can be life or death. Rolling off the throttle saved us from spinning; the engine was undamaged and put back into service!
Wear the right PPE. I failed to have my helmet on for stupid reasons (not uncommon in civvie flying 35 years ago) and was lucky. I had, however, paid for and certified a strong point for the cameraman’s quick release harness which saved his life. Normal ops for those days was to secure the harness to the seat belt anchor points which weren’t (and aren’t) certified for the lateral pull.
Wire cutters would definitely have prevented the wire from trapping the skid/crosstube. The economics of the day didn’t support them for me but for a military aircraft in the low level environment today it is almost criminal not to protect the crew and aircraft with wire strike protection.
Kudos to the crew and Chinook for a safe landing in this incident
For putting short term financial savings consistently ahead of safety? Sadly history proves your dispiriting comment as only too true. Unless of course I have misunderstood its cryptic meaning, in which case my apologies. Perhaps you might care to elucidate?
John Eacott: for your candor, calmness, and bravery, you have earned a well-deserved "Aussie, Aussie, Aussie - Au, Au, Au!" I wish I could touch your shoulder for good luck! An excellent and revelatory tale, Sir.
- Ed
- Ed
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The economics of the day didn’t support them for me but for a military aircraft in the low level environment today it is almost criminal not to protect the crew and aircraft with wire strike protection.
Although the H-C report is much talked about nothing has changed when it comes to accountability.
DV
Sorry, been away for a few days where the slow pace of life is matched by the internet speed and connectivity.
MoN - not sure how you got to see the lad’s photos but his dad has viewed the video and said it’s not much more than wingovers and positioning turns so please accept my apologies.
MoN - not sure how you got to see the lad’s photos but his dad has viewed the video and said it’s not much more than wingovers and positioning turns so please accept my apologies.
There has been a fair amount of discussion about wirestrikes, avoidance and results. I stuffed up many years ago and turned a perfectly serviceable Bell 206L into a cabriolet,
The wire went through the narrow gap between the top of the cutter and the disc and severed the pitch change rods. The aircraft did a gentle wingover, leading us to believe it was an intentional manoeuvre....until it hit the ground.
The pilot died of his head injuries, the commander was uninjured IIRC and the rear seat pax had a fractured femur.
Wire cutters aren't always the answer.
