Well, after a month of investigation, the problem seems to have been the T4.5 thermo couple probes...
The engineers looked at the master control box, starter relays, the starter, electro start valves, FCU, lubrication pump, fuel valves, injectors, etc..
The problem was eventually found to be one or more of the T4 probes sending false temperature readings to the VEMD. During the start, despite apparently taking T4 up to 800 oC (and higher on occasion, for a few seconds), it was actually much cooler and it was this that caused the stagnation, usually at around 36% Ng.
A new T4.5 harness (obviously, you need to buy all 4 new probes...) and she's now back to form.
Just a heads up, in case other EC120s show similar symptoms - you might save yourself a few $000s on fruitless investigation. This intermittent problem originally affected only 1 in 10 starts, but it got progressively worse until it was happening 7 times out of 10 and usually only when cold. Thanks for all the suggestions
So, intermittent problem has begun where the generator still works in both start / charge mode but intermittently no current is getting through to the battery. This gives "MAster Caution: Gen" and shortly afterwards the "Master Caution: Electronics". On/Off toggle GEN and ELEC RESET are not effective, though land and shut-down, it might come back fine.
I understand that the control of voltage flow to / from the battery is governed by the box behind the fuse panel in the cargo hold. This has 5 boards.
1. Anyone else had this problem? 2. Which of the boards / relays shoudl we investigate? 3. Does Eurocopter swap or fix individual boards?
Any other thoughts / ideas also welcome. We have checked all the wires and connections. Battery cap recently checked and is fine.
EASA AD 2011-0185 (Part I & Part II) (Modification of floatation gear) due at 1213.1 A/F hours or 17/02/2013
The only problem is, when contacting Eurocopter they say "speak to Zodiac, we don't have the parts" and Zodiac says "we can fit your request into the line schedule for early March 2013". And both Eurocopter and Zodiac say "this is not an AOG matter, as you can fly without floats". That really depends on the type of work your machine is doing! From 17th of the month I am losing hours/income.
Does anyone else fancy joining an effort to ask EASA to extend the deadline to a point when the parts might actually be available? After all, the floats still work (recent inflation check)
Lane 2 on my VEMD has an intermittent fault whereby the output from the computer doesn't quite make it to the screen in a coherent form, which displays a snowstorm of interference - as though it can't quite 'lock on' to the right channel. The computer itself is working fine and all the data can be read through Lane 1. It's probably just a dodgy 2 cent diode that's corrupts the image output signal.
Toptobottom, just a quick explanation that might shed some light. Screen 1 is the visual display of processor 1 and screen 2 the visual display of processor 2- 2 seperate computers. They each receive the primary info incase of a failure so you retain the primary info from the other processor. Each processor then have additional tasks ie 1 calculates the FLI and 2 The power check. So by excluding screen 2 you are excluding processor 2 which probably means processor 2 is gone. Unfortunately the processors can only be replaced by Thales thus the service exchange.
Exchange VEMD unit- 5k? that seems quite reasonable, the EDU we have in the A119 which is basically the same as the VEMD just not as well thought out, costs 55k per screen as a unit exchange, and if you think eurocopter are slow with the parts, you ain't seen nothing yet! We have been through 8 EDUs in 900hrs.
VP - thanks for the info. The problem with my unit is that 'processor 2' is always working fine. It survives all the diagnostics tests and thinks it's displaying the info correctly. If I turn it off, screen 1 can scroll through all the primary info e.g. Ts & Ps, voltages, FLI, etc. on Screen 1 and when I keep screen 2 on and scroll, it will perform all the different functions perfectly, including a power check - it's just that you can't see it...
Whatsarunway - 8 EDUs in 900 hours?! Surely, that's a warranty job though? Even Agusta must realise that isn't acceptable?! 55k and huge waiting lists also aren't acceptable, but they know we don't have a choice...
Any one elaborate or correct my recent rumour that Eurocopter is set to scrap the B2 keep the B3e and turn the screws up on the power for the ec120 ( how much I don't know) so that it can actually lift full pax and fuel in the same universe