Gents. The higher risk factor is depressurisation,
Precisely. However, currently on T7 in that area, company procedure is "4 mins at FL 290/17 mins at FL 250"....!
and you better not be off track avoiding weather.
By the way, try giving Hotan (HTN) or Kashi (KHG) a call next time you go past at night. You might be surprised at the response (or lack of). These are supposed to be boltholes in the event of dire emergencies (cargo fire, depress). The towers seem to be manned in daylight only, so you are faced with a long slog to Urumchi or Beijing (24 hour airfields), as the chances of getting someone up there pronto on a winters night to turn on lights, activate facilities etc etc at these other places are fairly slim I would imagine.
Lets not even get into the perennial Hotac issues. Combined with high terrain at these airfields, it all compounds the decision-making process. As aviators, we strive to reduce risk, but in doing so we often find ourselves at odds with the beancounters. I am not sure if they attend CRM courses, but I often wonder if we are on the same path when it comes to (not) lining up the holes in swiss cheese. We now have 3 hour ETOPS for twin engines; We are now adding ultra high terrain into that mix.
Personally, once I approach the border at Porpa (westbound at night), I go high speed to get through that area asap (to hell with low cost index),and also to increase the driftown speed margins. I also plan (in case of depress) to keep going on towards the "lower" terrain futher ahead in Pakistan, rather than turning back (over The Hump), to a China alternate (contrary to the suggested option in that part of the escape route) when you are already in Pakistan territory. Trying to cross back into Chinese airspace with attendant ATC language problems in an emergency would definitely present some challenges.
I have no doubt that these escape routes were designed (probably some time ago, with specific aircraft in mind) with the best of intentions by the engineers, but there are a few anomalies that deserve further scrutiny.
Having said all this, Eastbound over the Himalayas as dawn breaks on a clear day, provides a spectacular view. Not to be missed. VMC is never a problem.