If the Mk2 Chinook software was not to blame for the Mull of Kintyre crash in 1994, which the MoD insists is the case, then why did they decide to write their own Fadec engine control software for the Mk3? Of course that ended up being a pigs ear too.
http://news.bbc.co.uk/1/hi/uk/8438659.stm
http://news.bbc.co.uk/1/hi/scotland/1800727.stm
http://en.wikipedia.org/wiki/1994_Scotland_RAF_Chinook_crash
http://www.timesonline.co.uk/tol/news/politics/article6808604.ece
http://www.computerweekly.com/Articles/2009/06/04/236302/chinook-crash-critical-internal-memo-on-software-flaws.htm
http://www.chinook-justice.org/
"Insiders have disclosed that the MoD [...]