You may be aware that we have not been able to fly to McGrath (Nikolai, Takotna) when it has been extra cold, even though the weather has been clear and the winds calm. On these days we’ve had to wait until the sun has warmed the surface temperatures up to the aircraft’s certified cold temperature limit, which is -40ºF for the Pilatus, and -31ºF for the Caravan. The aircraft manufacturer establishes these limits in order to minimize the chances of something breaking due to the extreme cold, where for example, lubricants lose effectiveness.

You may have noticed us extending our flaps at a higher than normal altitude on days that are near, but not colder than the limitation. That’s because there is a temperature inversion on those days, and it is actually warmer a few thousand feet above the surface, so by extending the flaps in the “warmer” air, we minimize the risk that they would get stuck before fully extending for landing (which is not catastrophic, but not good either).

Thanks for your patience on these extra cold days!

- Dan Owen, D. of Operations