Creamie. In a word - probably wrong.
There is no doubt reverse flow compressor washes via the igniter boss would have marginally enhanced the benefit of compressor washes, but I know of only one other operator who uses that procedure and generally, PT6 engines don't fail. There is no doubt more frequent Boroscope inspections would have revealed the damaged compressor turbine blade(s) which eventually parted company with the CT Disk.
But the cause of the problem was mineral build up on the CT Blades from using Horn Island tap water, knowing the island was heavily mineralised (there is a gold mine and significant mineral deposits on the island) we didn't "tweak" to the fact the treated water may not be "potable". (I don't recall exact details of the analysis, but do recall the silica content was 18 times the acceptable level.)
We relied on engine computer trend graphs which, strangely, did not detect above average degeneration in the engine performance. Turco power recovery washes did give marginally improved results, but the fact was that plain water washes resulted in mineral build up, rather than demineralisation.
After obtaining the laboratory reports and Pratt's report (their manuals do not define "potable" water), we installed a water purification system and the US$250,000 engine failure problem was solved.
I should have known better - in PNG we used distilled and demineralised bottled water in our 90 odd PT6 engines.
I shudder to think of how many turbine engines in Australia may be being washed with unsuitable water. In many western Queensland towns reliant on bore water for example, the PH is between 7 and 9 with significant amounts of disolved salts - totally unsuitable for engine washing - and yet I have seen turbine engine washes carried out with the same town water.
Pratt's agreed that engine washes before the first start of the day using the first start as a drying run was acceptable (particularly in our environment where the sector times were so short and no outer island ground power) and would result in less cycles and a higher average cycle time. (i.e. higher engine hours per start cycle.) Indeed, morning washes would result in a "cleaner" engine than one washed at night then subject to the night air (even with engine plugs installed), particularly in an engine operating in salt laden air.
Pilots can be "approved" to carry out compressor washes via a compressor wash ring, however because the igniter is lock wired, only a LAME can carry out igniter removal and replacement. I also had some concerns with the prospect of removing and replacing the igniter around 3,000 times in the life of an engine - any damage to the thread and life could get
very interesting with a blow torch under the cowling!
The ATSB were correct in the fact the engine failed due to loss of three CT Blades - that part was easy. However, I do not believe they were correct in their findings of all the contributory factors.
But I accept we should have been far smarter than using Horn Island tap water for engine washes!
In all fairness, I have always found my dealings with BASI/ATSB infinitely more professional than my dealings generally with CASA. I remind you of the Coconut Island accident where your mate Fumbles made the ludicrous decision, from thousands of miles away in Canberra, that the accident was caused by
“corrosion on the left engine mixture control rod, causing the engine to fail”. BASI immediately released an interim report which totally refuted the absurd Fumbles claim. In fact, the mixture control rod broke from impact forces.
"The left propeller showed little evidence of rotational damage. The propeller had not been feathered. Laboratory examination of a failure of the left engine mixture control rod confirmed that the failure occurred at impact as a result of impact induced stresses. Examination of the engine did not reveal any condition likely to have prevented normal operation."
http://www.atsb.gov.au/aviation/occu...ail.cfm?ID=171
Ultimately, both BASI and the Coroner found the cause of the accident was a truck driving across the runway.