A very sad story.
There are clear elements of 'mission creep' in this organisation's op. Even at 1500, those guys would have only cleared the pass by a few hundred feet, and there is not a not of room to conduct a 180, right at the top of the pass, with rapidly rising high ground on either side.
We should all examine our daily/nightly ops and ensure that the mission does not grow beyond the capability of the crew or the aircraft...
On 'pledge'...is something lost in the translation there? Are they referring to the mission, or do they really mean 'pledge?'