Scotland Helicopter Crash

[Magog]

Zad said:

Magog said:

It looks like the passage in the bulletin relating to the Central Panel Display System could be key. Reading between the lines, did the pilot get any warnings at all?

It is best to read the PDF of the report really, it is only 9 pages long and is relatively easy to understand. Here is the relevant part, but it is best to read it in the full context:

AAIB Report said:

Recorded data
Data from the helicopter
:
The contents of the non-volatile memory (NVM) from the equipment known to record data have been successfully recovered and are being analysed. The majority of the recorded data have no form of time stamp. So, whilst the order of some of the snapshots can be determined, their relative timing is unknown. Other systems use time references but ones that are not directly linked to UTC.

The Warning Unit has provided information on the order in which warnings were triggered during the flight but not when they occurred. The unit recorded the normal warnings associated with starting the helicopter, followed by a warning free status. It subsequently recorded intermittent LOW FUEL 1 warnings for the left fuel supply tank, then a permanent LOW FUEL 2 warning for the right fuel supply tank. This was followed by a further temporary LOW FUEL 1 warning, before it became permanent for the remainder of the flight. These LOW FUEL warnings are triggered by thermal sensors in the supply tanks.

An alarm gong was also recorded followed by intermittent warnings relating to low rotor rpm. The penultimate warning recorded related to the battery discharging, which occurs when there is insufficient engine-driven generator power. The last warning related to an autopilot system failure. Investigation into the possible causes for the individual warnings is continuing.

It was the passage following that, in the context of those above which caught my eye, specifically the last sentence;

AAIB Report said:

The Central Panel Display System (CPDS) displays cautions and fuel status information
to the pilot. It also records internal display system faults but no information relating to its
indications. The displays did record flight duration and work is being carried out to link this
duration, and the conditions required to start and stop this recorded duration, to the flight
path of the helicopter. A fault relating to one of the display systems was recorded and further work is being undertaken to establish the meaning and possible causes of the fault.

Looking at Scuffers post above, it looks like the warnings are displayed on the CPDS, is it a possibility that the warnings were not displayed, or not displayed correctly? The equivalent of the ECU recording a fault code but the dashboard light not coming on in a car? Is that technically possible, or are warnings also displayed elsewhere. I will be the first to admit that I have next to no knowledge of helicopter avionics.

[Scuffers]

Magog said:

Looking at Scuffers post above, it looks like the warnings are displayed on the CPDS, is it a possibility that the warnings were not displayed, or not displayed correctly? The equivalent of the ECU recording a fault code but the dashboard light not coming on in a car? Is that technically possible, or are warnings also displayed elsewhere. I will be the first to admit that I have next to no knowledge of helicopter avionics.

I think that's clutching at straws...

[Eric Mc]

With things digital, anything is possible.

[Scuffers]

Eric Mc said:

With things digital, anything is possible.

The CAD display us only one screen, and it's not the only one.

The bigger point is that in case of conflicting info, land first, ask questions later.

At the end, having lost one engine, he still had approx 2.5 minutes of the other engine to get it in the ground, he not only failed yo do thus, but also failed to auto rotate.

[Eric Mc]

You MAY be right but until the FULL circumstances are known, I think it is rather presumptious of you to lay complete blame at the door of the pilot.

[Scuffers]

Eric Mc said:

You MAY be right but until the FULL circumstances are known, I think it is rather presumptious of you to lay complete blame at the door of the pilot.

And when have i said that?

Please read what i have posted on this thread, not just the last post.

[Stuartggray]

If one engine is faulty, is it possible to switch off the wrong engine by mistake?

[Scuffers]

Stuartggray said:

If one engine is faulty, is it possible to switch off the wrong engine by mistake?

How was one engine faulty?

One engine quit because of no fuel, nothing to switch off...

[Mojocvh]

Eric Mc said:

With things digital, anything is possible.

sure is, look at what were doing right now...

[Vipers]

Stuartggray said:

If one engine is faulty, is it possible to switch off the wrong engine by mistake?

Wasn't there something similar when a plane heading for Birmingham did that very thing, shut off the working engine, just cleared the motorway I seem to recall.

I think some coffee was spilt on the controls or something, so long ago Imsaw the documentary on T.V.

Different situation I know but fundamentally same thing.

[pattyg]

Vipers said:

Wasn't there something similar when a plane heading for Birmingham did that very thing, shut off the working engine, just cleared the motorway I seem to recall.

I think some coffee was spilt on the controls or something, so long ago Imsaw the documentary on T.V.

Different situation I know but fundamentally same thing.

That was the Knebworth crash.

[NailedOn]

pattyg said:

That was the Knebworth crash.

Kegworth.
East Midlands Airport
A Boeing 737-400.
The pilots shut down the wrong engine after one failed.

[anonymous-user]

It is possible to switch off the wrong engine by mistake, but that didn't happen in this case as the position of the control switches post impact indicates both engines were in "run" mode.

[Vipers]

pattyg said:

Vipers said:

Wasn't there something similar when a plane heading for Birmingham did that very thing, shut off the working engine, just cleared the motorway I seem to recall.

I think some coffee was spilt on the controls or something, so long ago Imsaw the documentary on T.V.

Different situation I know but fundamentally same thing.

That was the Knebworth crash.

Got it in one

[aw51 121565]

NailedOn said:

pattyg said:

That was the Knebworth crash.

Kegworth.
East Midlands Airport
A Boeing 737-400.
The pilots shut down the wrong engine after one failed.

Also painful lack of experience at piloting the thing and interpreting its behaviour and instruments (from memory) leading to erroneous decisions (to shut down the wrong engine) and the subsequent crash .

[TheSnitch]

I am not sure if anyone has highlighted this from the report yet, I just noticed it now.

AAIB report said:

At 2045 hrs on 29 November 2013, the helicopter departed Glasgow City Heliport (GCH), to
support police operations. On board were the pilot and two police observers, each of whom
was in possession of a set of Night Vision Goggles (NVGs). The helicopter had 400 kg of
fuel on board, giving an endurance of approximately 1 hour and 35 minutes3

There is then a footnote relating to this

footnote said:

. Using an average fuel consumption of 200 kg/hr and the operator’s Final Reserve Fuel of 85 kg - Final
Reserve Fuel being the minimum amount of fuel with which pilots should plan to land.

So, they had been flying for 1 hour and 37 minutes at the time the accident occurred, pretty much at the end of the recommended endurance and the remaining fuel - 76kg - had fallen below the minimum recommended level of the final reserve.

So basically, they were pushing the envelope, and were right at the end of their normal recommended flight. I'm guessing that the reserve level for fuel is probably in line with the level at which the supply tanks no longer fill automatically.

The report later says

AAIB report said:

The fuel pump switches were examined at the accident site and it was found that the No 1
and No 2 prime pump switches (pRIMe I and II) were set to the on position and the fore and
aft transfer pump (XFeR F and A) switches were set to the oFF position.

So can someone help me here - should the XFeR pump switches have been in the off position during the flight?

Apologies again for the questions - like I said, I know sod all about these things. Thanks.

[Scuffers]

TheSnitch said:

So can someone help me here - should the XFeR pump switches have been in the off position during the flight?

Apologies again for the questions - like I said, I know sod all about these things. Thanks.

Yes, normally off whilst travelling.

Other thing is that if you run them with an empty tank they get damaged (according to the manual)

[TheSnitch]

Scuffers said:

TheSnitch said:

So can someone help me here - should the XFeR pump switches have been in the off position during the flight?

Apologies again for the questions - like I said, I know sod all about these things. Thanks.

Yes, normally off whilst travelling.

Other thing is that if you run them with an empty tank they get damaged (according to the manual)

Thanks for that - just one more question, then.(Sorry, I sound like Columbo)

If they are normally in the ''Off'' position, presumably one therefore has to manually switch them to ''On'' in order to access the fuel in the reserve, presumably in response to a low fuel warning. So at what fuel level would an alarm first sound, and how long in normal flying conditions would that be before the engine would flame out?

[Scuffers]

TheSnitch said:

Thanks for that - just one more question, then.(Sorry, I sound like Columbo)

If they are normally in the ''Off'' position, presumably one therefore has to manually switch them to ''On'' in order to access the fuel in the reserve, presumably in response to a low fuel warning. So at what fuel level would an alarm first sound, and how long in normal flying conditions would that be before the engine would flame out?

yes no..

yes it's a manual switch (well 2 actually, front and back of the tank)

No, I believe it's more to do with what your doing at the time as to if you have them on or off, there is an alarm to tell you they are running dry, (and that does not mean the main tank is empty, it can be because of attitude change of the 'copter).

some pilots elect to just leave them running all the time and only turn them off when the main is empty....

other point to remember is the supply tanks are not small:





you might find this helpful:

http://www.airbushelicopters.com/site/en/ref/FAQ_1...

Edited by Scuffers on Monday 17th February 10:22

[onyx39]

aw51 121565 said:

NailedOn said:

pattyg said:

That was the Knebworth crash.

Kegworth.
East Midlands Airport
A Boeing 737-400.
The pilots shut down the wrong engine after one failed.

Also painful lack of experience at piloting the thing and interpreting its behaviour and instruments (from memory) leading to erroneous decisions (to shut down the wrong engine) and the subsequent crash .

was a spanking new aircraft (6 weeks old IIRC), and the particular instruments that the pilot did not interpret correctly were apparently far more reliable than on the previous versions of the aircraft.
As such, the pilot chose to "not accept" their reliabilty... I think.