Light Aircraft down in Staffordshire

[Pace]

As I said before, I more inclined to believe some sort of problem leading to a possible stretching of the glide and stall with subsequent nose down descent into the ground.

Bose

The witness who seemed quite a serious calm sort of guy reported a sharp wing dop followed by an almost vertical dive into the ground. Another witness reported the engine sounding like a high speed drill which for a non pilot was quite an accurate description of the sound of a high rev diving aircraft.

There were no radio calls made in ref to a rough engine or engine failure and subsequent attempted off field landing. Tricky one!

Pace

[S-Works]

Which would indicate a stall and probable spin entry. So back to my point about the cause rather than the visible symptom?

[execExpress]

"Which would indicate a stall and probable spin entry."

FWIW thats the best sense I can make of the reports so far.

"So back to my point about the cause rather than the visible symptom?"

Cold day, lots of cabin heat, cracked exhaust, carbon monoxide poisoning of the PIC is a leading potential scenario. Wouldn't be the first time. Sadly, won't be the last. It doesn't happen often, but does happen.

Small electronic CO2 detectors with audible alarm are available - can go back in the flight-bag or be left in the aircraft after flight.

Is the CO2 risk worth some outlay on a detector? Like having a liferaft after leaving a ditched aircraft - if it happens to you - there is no question - it is worth it. I am not sure there is a better way of mitigating this risk.

[Pace]

Bose

It could indicate a whole host of possibilities!
Really depends on what height it occurred. A nasty wing drop could have taken the pilot by surprise leading to an over recovery, he could have entered a spiral dive mistaken it for a spin and not recovered from the resulting dive. He may not even have been at the controls ie incapacitation. Something could have broken or seized?

His passeneger in the right seat may have contributed? The list goes on.

The height at which the witnessed episode commenced would be very telling. If indeed it was 100 to 200 feet then a stall stretching the glide could be the reason.
If the witnessed episode commenced much higher then its unlikely.

The shear destruction of the airframe into unrecognisable fragments would indicate a very high speed impact from altitude as would the high speed drill sound of the engine/prop but like you I am only guessing.

Lets hope the AAIB manage to piece together enough from this tragic accident to get a likely cause.

Pace

[S-Works]

The 415kv lines that the aircraft seemed to have hit could have been a likely contributor to the scale of devastation.

Sometimes the simplest scenario provides the simplest answer. Looking at the history of accidents in this type their is a recurring theme that seems to come to my mind at least.

Reading the comments about the pilot it strikes me that he was a safe and conscientious aviator who would not have been show boating low level. So looking at other reasons for them to end up so low over a railway track leaves me with a mechanical failure that the pilot was doing his best to salvage.

My gut feeling is a possible power problem, attempt at a forced landing, poor choices to put down, an attempt at stretching the glide to clear the railway tracks and subsequent stall spin.

[172driver]

My gut feeling is a possible power problem

And all witnesses report a high-revving engine ??

[S-Works]

My wife thinks the engine on my cessna sounds high revving at idle. If the engine was running it could sound 'high revving' to the untrained ear. This would not preclude there being a power problem that prevented the aircraft maintaining height.

I have an open mind to any other possibility but as I said quite often the simplest answers are usually not far from the reality.

It is interesting as an Instructor to see how people struggle with flying accurate PFL's during the 2 year review flight. Just because it is a skill that is rarely practised by most. It is very easy to get on the back of the curve during practice so think about it during a real emergency?

[Pace]

My concern too was the high revving engine a stall low level into power cables and you would expect a lot of large pieces of wreckage rather than the powder remains. The cables were destroyed which also indicates a high speed collision with them too.

The high speed electric drill sound reported by a non pilot did it for me because that is exactly what a high rev high speed dive sounds like.

We are all guessing so lets hope the AAIB have more.

Pace

[S-Works]

Pace, I would expect quite the opposite. Hitting 415Kv lines would have caused an explosion and intense fire in my experience. When I worked for railtrack we had to do a 'person' course that would allow us trackside and one of the videos showed a van bringing down the high voltage cables. It was flash incinerated in seconds.

The TV images remind me of this video acclerated by the Avgas I suspect.

[vanHorck]

i don't know the location where the crash happened.

If he was higher up when the problems began, surely he would have made a call, as pushing that talk button does not preclude any simultaneous action in the cockpit, I think it would be second nature to do so.

In that case the question is natural, to ask if he was on an approach to a field.

Carbon Monoxide poisoning could explain descending (at increasing speed) without a call and perhaps the sharp wingdrop at the first contact with the powerlines.

The alternative of flying low (without being on an approach) and slow and stalling when trying to avoid the powerlines would be awful indeed

[Pace]

Van Horck

As far as we know there was no call made of any problems. The Pilot was in his mid sixties. For all we know it could have been pilot incapacitation with the passenger not even knowing how to use a radio or how to fly an aircraft.
It is all guesswork and as such important to keep an open mind.

Pace

[S-Works]

Or it could just have been that he was non radio(by non radio I mean not talking to anyone) and the incident arose so quickly that his priority was to aviate before communicate.

I hardly turned my radio on in the last week with no one to speak to.

[west lakes]

Hitting 415Kv lines

Gents sadly they hit the 25,000V West Coast main line power cables & catenary. From memory these can take something in the region of up to 1000 amps before disconnecting, so apart from the energy of the crash you may be looking at something like 25MW (million watts) of electrical power dissapation as well.

[IO540]

On a short circuit, the circuit breaker up the line would have tripped in a small fraction of a second.

At a descent rate anything like that reported by the witnesses, the time between slicing the power cables and hitting the ground would be so short that the power cables would not have made any significant difference to their trajectory, which was apparently more or less straight down.

[vabsie]

For my own benefit - Does Pilot Incapacitation mean heart-attack?

[S-Works]

On a short circuit, the circuit breaker up the line would have tripped in a small fraction of a second.

IO, it does not work like that on the railway power grid or the national power grid for that matter.

I have the exact details from the course somewhere but it is something to do with the way power is drawn by the engines that would cause a CB to trip out all the time. Even when severed it is possible for the lines to remain live. The lines are also capable of generating their own electricity from static accumulation.

[Pace]

For my own benefit - Does Pilot Incapacitation mean heart-attack?

It can mean a heart attack but could mean any condition where the pilot was unable to fly the aircraft.

Pace

[AMEandPPL]

a very wide term . . . . . . .

For my own benefit - Does Pilot Incapacitation mean heart-attack?

Yes, it certainly could do, but, as Pace says, it could also mean anything whereby normal control of the aeroplane by the pilot is reduced or prevented. The list could be almost endless . . . . . . .

Heart attack, stroke, epileptic fit, poisoning ( CO, food);
even anything which, due to severe pain, is totally distracting, eg renal colic.

And we all remember the pilot who was struck blind late last year . . . . .

[Pace]

I am tending to lean towards incapacitation of either the pilot or airframe /controls bar the pilot doing something stupid aerobatic wise.

But doing something stupid aerobatic wise could lead to airframe /control problems.

The pilot was fairly old mid sixties so unlikely to be a tearaway hot rod although you do get some.

He was experienced in an aircraft he had flown for years. That would mean it fitted him like a glove. He would know every twitch or burp it made.

The PA28 140 had the old slab wing which was the most stall resistant and docile wing used even today on the seneca twins.

I dont think there are any indications to show an engine failure, glide and stall spin.
unlikely to a pilot who knew the aircraft so well.

No radio calls would indicate something abrupt in either the pilot or the airframe. The vertically down and destruction in the accident site to me means from altitude.

Incapacitation / airframe control problems / possible semi aerobatics? which is quite a wide spectrum of possibilities. But hey my instincts might be totally wrong.

Pace

[dont overfil]

I have twice in (newer) PA 28s discovered excessive movement in the "stablator" bearing. When pointed out to the engineers the AC was grounded immediately.
Is it possible that it could fail completely? Does the 140 have the long counterbalance, which I believe was subject to an AD?
DO