The airline that I flew 757's for ten years ago was in the habit of using BGBW as a non-ETOPS alternate from time to time. I was in the habit of refusing these flight plans. As I had a minor management position, I took the liberty of writing to the chief pilot at Air Greenland to inquire how they prepared for their 757 operations there. I don't have his reply handy; it is somewhere on a hard drive around here somewhere. But in any event, if I recall correctly, he said that it was a required simulator check item, and that it was not uncommon for pilots to fail that item and require re-training.
My analysis of using this airport as an alternate is below; I based it on the engine-out condition that would be a worst-case scenario requiring diversion to BGBW. Of course, we would have been doing this at night... :roll eyes:
Note: this was prepared ten years ago. I don't know what might have changed...so, obviously, NOT FOR USE IN NAVIGATION applies!
"There is only one instrument approach that is usable for 757 aircraft at Narsarsuaq. This is the NDB DME-1 to runway 7. This approach requires an MDA of 1800 feet for category C aircraft, and defines the MAP at 4.0 miles from the NDB DME. The runway is one mile closer, thus requiring a descent gradient of 5.66 degrees from the MAP to landing. This will require a descent rate of 1200 fpm at 120 knots of groundspeed. There is no way to consider this descent as a stabilized approach under standard guidelines, including our own FOM.
In the event of a missed approach, a minimum climb gradient of 4% is required. This gradient assumes that a missed approach is initiated at the MAP.
In section 4.12 of the 757-2Q8 Airplane Flight Manual, the flaps 20 approach climb chart indicates that, at a weight of 185,000 lbs and with engine and wing anti-ice on, the climb gradient will be 6.75%. A further reduction to 6.25% is required for ice accumulation on the airframe. Thus, from the MAP, a missed approach is feasible.
However, the same approach allows an MDA of 1500 feet for category A and B aircraft. In this case, the minimum climb gradient in the missed approach is 6%. Thus, it is reasonable to assume that, somewhere shortly after the MAP while descending to land, a 757 with one engine inoperative and ice on the airframe will quickly cross a point at which the minimum climb gradient could not be achieved. Further, the missed approach procedure is predicated in initiating the miss at the MAP.
An additional point is that all turns in the missed approach, initiated at the MAP, must be limited to 160 knots. It is reasonable to assume that, after the MAP, a slower speed would be required. However, we have no information on this."