Engines,
my point was that at the time of purchase of the Chinook (done at the last minute because there was money left at the end of the financial year after cx of the original order a few years before !) Boeing refused to act as DA.
In respect of info from the USAF when I was a member of the HEART we visited Marshalls and were informed that they had been contracted to look at other air forces experience of Hercules serviceability. The USAF refused to co-operate, so most of their info came from the RAAF. Problem was a large percentage of it was 'A' model stuff. A very different beast in many ways to the 'K'.