Cazatou stated clearly a very important factor in this flight when he wrote <<You will also be aware that the Operating Restriction as regards Aircraft Weight was adopted as a precautionary measure to ensure that the Chinook remained within the safe, single engine flight regime.>> - something I had tried to explain before was that there was ample power to spare in the event of an emergency manoeuvre being required, had the engines not had to spool up from the minimum matched level they were at to keep in the air while coasting in letting the speed wash off - had they been maintaining their high cruise speed, a cyclic climb could have instantly twitched them up a couple of hundred feet in the 4 seconds after it appeared that they started to take evasive action.