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-   -   Police helicopter crashes onto Glasgow pub (https://www.pprune.org/rotorheads/528850-police-helicopter-crashes-onto-glasgow-pub.html)

Thomas coupling 16th Dec 2013 19:35

Thank you A Sapper on behalf of all police drivers in the UK.:ok:

PS: Were you a prisoner or passenger whilst airborne? :O

DucatiST4 16th Dec 2013 19:44

Is it fair to say that most Police and HEMS Pilots are ex military?

Sven Sixtoo 16th Dec 2013 19:48

I have no statistics, but I believe yes that is a reasonable statement (I applied for lots of such jobs when I left).

Do remember that military pilots vary a lot in their skillset and experience (end of serious answer). Some non-British are, amazingly, quite competent. Army tend to be good at small stuff, Navy tend just to be good (operating off a ship sharpens your senses in all sorts of ways), RAF green tend to be good at big and complex, RAF yellow are of course the finest pilots on or off the planet!

You're not a journalist by any chance? I have been asked questions like that in the past, and only found out 2 days later that I was talking to the 5th estate.

Iain

DucatiST4 16th Dec 2013 19:54

No not a journo, I friend of mine is just finishing her PPL(H) with the intention of flying for the Police one day. The adverts I've seen want 2000 hours PIC so there won't be many amateur pilots who can manage that without the Queen paying for it! I need to break it gently to her that she's got no chance!
Sorry I'm not really on topic with this.

SilsoeSid 16th Dec 2013 20:12

Don't tell her that Duc, the majority of the pilots at our unit are not ex-mil and one if them is female. Your 'friend' has every chance going to fulfil her dreams. The problem for you is that if you feed her downers, you're not going to be part of those dreams!

If you keep her pecker up, she'll keep yours :ok::E

212man 16th Dec 2013 20:23


What I do know is that if the engines aren't chopped by the time the Nr gets down to 60%, they will re-engage
No, as HC and others said earlier, if you have wound off the throttles to idle you are now N1 governed and the N2 is simply a function of the residual thrust. The engines will not respond in that governed range, and that's true of any aircraft - FADEC or otherwise.

(if you don't believe it, try sitting on the pad with the engines at idle and then raise the collective - the Nr will decay with no engine response)

DucatiST4 16th Dec 2013 20:48

Mr Sid, she's not my "friend" yet but I'd like her to be so i'll bear your advice in mind :-)

FlightSpanner 16th Dec 2013 21:08

I'm with you 212, idle on all the types I'm rated on (Engineer) is an N1 control function, haven't worked the 135 for a few years but I'm pretty sure it is the same, you may well get 60% N2 but as you say the N2 will slow if the collective is raised and of course no longer indicate 60%.

Can you do a rotor braked start on the EC135? like other models? If so then this proves the governed N1 control at idle.

FS

Feline 16th Dec 2013 21:19

Telegraph reporting quantity of fuel could be overestimated
 
Report in Daily Telegraph filed at 9:06pm 16th December.

Not sure whether this has been fully covered in this forum before (so many posts!). But if the red "low fuel" light appeared without any prior warning, that could very easily explain why the engines suddenly died and the rotor wasn't turning?


However, the manufacturer Eurocopter has issued a safety alert to operators around the world warning that fuel gauge errors were found and repaired on “some" EC135 aircraft.

It said the quantity of fuel in the supply tanks could be over estimated and in the worst-case scenario a red “low fuel” warning could appear without any amber warning appearing first.

It has issued a safety information notice to all operators of the Eurocopter EC135 aircraft, warning that the system may not work properly and must be checked.

The fault was discovered by Bond Aviation Group last Wednesday evening - 12 days after the fatal crash in Glasgow - in a North West Air Ambulance aircraft.

212man 16th Dec 2013 21:20

SS, I suggest you go away and think about it. I'm not disputing the

imho the engines were deliberately shutdown to prevent further fatalities.
bit, but the rest (engines at idle, responding to decaying Nr) does not bear scrutiny. I don't need to read a book - I've done a bit of it for real, thanks for asking....:ok:

Edited to add:


The N2s wound down to 60% and the Nr decayed until it reached the N2 needles ... Guess what! .... The rotors re-engaged and we sat there realising
Of course the needles re-joined, but that's not the same as being governed. Without engines the Nr will tend to zero, over time, but with residual N2 from idling engines the Nr will stop decaying. I hope you know this and are just chucking grenades! (the alternative is dismaying...)

RVDT 16th Dec 2013 21:33

Sid,

When do you think the engines were shut down?

Considering there is compelling evidence that the blades were not rotating when the aircraft hit the roof?

212man 16th Dec 2013 21:40

Edited to add:


Quote:
The N2s wound down to 60% and the Nr decayed until it reached the N2 needles ... Guess what! .... The rotors re-engaged and we sat there realising

Of course the needles re-joined, but that's not the same as being governed. Without engines the Nr will tend to zero, over time, but with residual N2 from idling engines the Nr will stop decaying. I hope you know this and are just chucking grenades! (the alternative is dismaying...)


and the airframe embedded, either the blades will thrash themselves or the input shaft will break?
That's a separate discsussion! (whatever embedded means)

SilsoeSid 16th Dec 2013 21:44

RVDT

Sid,
When do you think the engines were shut down?
Considering there is compelling evidence that the blades were not rotating when the aircraft hit the roof?
Possibly at the same time of the the twist grip action, when he realised how bad the situation was. If you think about it, you could add to the reference cards for that particular emergency, 'If time permits .... '.

RVDT 16th Dec 2013 21:51

Sid,

How much power do you think it takes to drive the blades at 60% flat pitch.

A standard procedure on the old S-76 A with Allison C30's was to start and stop
with one engine in idle and the rotor brake ON.

Brake ON start an engine - brake OFF - start second one.

Shutdown one engine - Brake ON until blades stop - shutdown second one.

Even with 2 engines at idle the brake was man enough to stop the main rotor
as long as it stopped without a blade being over the exhaust.

I know the brake in a 135 isn't up to it but the drive train certainly would be.

At MIN FLOW I would guess that each each might make 30 HP at best.

212man 16th Dec 2013 21:54

This discussion is less than depressing...

Thomas coupling 16th Dec 2013 22:22

Lets' stick to topic eh and you two go talk behind closed doors.

SilsoeSid 16th Dec 2013 22:44

Someone once told me , "Question everything", I replied Why?

airpolice 16th Dec 2013 22:48

Sid,

Can you describe the finger manipulation involved in shutting the engines?

Can you do it "just" by rolling the twist grip all the way closed?

MightyGem 16th Dec 2013 23:03


Is it fair to say that most Police and HEMS Pilots are ex military?
At the beginning of 2011, before all this NPAS malarky started, there were 119 full time Police pilots in the ASUs in England, Wales and NI(I didn't include Scotland for some reason), not counting floaters.

Of the 119, 97 were ex mil with 56 ex Army Air Corps, 19 ex Royal Navy, 11 ex RAF and 11 ex Royal Marines, leaving 22 as "civilian" pilots.

No idea what the numbers are at present.

airpolice 16th Dec 2013 23:04

Check PMs, you know who you are.............


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