REGARDING Stuart Campbell’s letter (June 13), commenting on Neil Mackay’s article ("Could new mobile phone link solve mystery of the Chinook tragedy?", June 6) as the author of the book in question (The Inconvenient Truth), I wish to respond to Mr Campbell’s points.

* Mr Campbell claims the effect of mobile phones could not have contributed to the accident. He does not say why he disagrees with the MoD’s admission that they could cause serious problems with the automatic flight control system, fuel computers, navigation and communications systems. To make this clear, the article reproduced MoD’s statement in full.

* Mr Campbell claims the pilots broke the safety rules. In fact, I believe it was the RAF air staff who broke the most basic safety rule – they declared the aircraft airworthy, when it was not to be relied upon in any way. In 2011 Lord Alexander Philip, in his Mull of Kintyre Review report, confirmed this was "mandated" upon the RAF. Those on board were sent to their deaths on the back of this false declaration. Had they known this, would they have boarded?

* Mr Campbell claims the crew made a navigation error. In fact, the evidence shows they knew where they were, how high, how far from the lighthouse, and how long it would take to get there. (Primarily because they received a one-minute alert on their navigation computer, and were flying clear of cloud and in sight of the surface.) The navigator selected the next waypoint, and left his navigation system in a mode commensurate with remaining in visual meteorological conditions. The pilot's instrument settings confirmed he had no intention of going near the high ground. In 2012, MoD finally admitted that an undemanded flight control movement could occur when the intended turn away from the lighthouse was attempted; for example, turning right when commanded to turn left, accompanied by changes in altitude. The book provides examples of other fatal Chinook accidents caused by this.

These known facts were concealed from the fatal accident inquiry in 1996, a deceit I believe crucial to Lord Philip’s recommendation that the findings of gross negligence be set aside.

The key question today is why the Lord Advocate has refused to order an investigation into (a) 29 deaths on Scottish soil, and (b) his inquiry being misled. Is the truth inconvenient?

David Hill, Yate, South Gloucestershire.

* I SINCERELY thank Neil Mackay for his excellent and well-researched article about the RAF Chinook accident that ended the lives of my husband and his brave colleagues in 1994. I am always amazed that so many remember that day as vividly as myself and my family. Strangers still tell me: “We always felt something was not right with that flight.”

I'm saddened to read Mr Campbell’s nonsensical letter condemning both the article and the most recent book, The Inconvenient Truth by David Hill (a highly qualified ex MoD engineer). Mr Hill has spent much of the last 20 years researching air accidents, supporting families and publishing factual highly technical evidence for no personal gain. Each of his previous books illustrates yet more overlooked, ignored and damning faults/system problems with the Chinook. When technical people work from the their heart and soul for no personal gain one knows there is great injustice – one that blamed qualified RAF special forces pilots for an obscene 17 years. When Mr Campbell records the families of those brave men exhibiting “unseemly jubilation” in the 2011 hearing that their names had been cleared then one knows he has a serious lack of compassion and understanding. I myself, cried tears of relief for the pilots' families on that day.

My tears were rapidly followed by frustration that further investigation seeking the real cause and culpability was to be refused into the 29 deaths on t Mull of Kintyre on that tragic day in 1994 that changed my family's life forever.

One must ask: Is the truth inconvenient or too shocking to legally and correctly uncover ?

Dr Susan Phoenix, widow of Det Supt Ian Phoenix, Dorset.