BA38s engines "Hesitated"
Dear Green-dot,
Point taken, the AD 2008-02-05 does involve ground fog icing conditions only, and that in e x t e n d e d periods of idle power.
The BA38 probably flew a very extended period at "flight idle" power, from FL400 to 780 ft. Since engines have slightly different "lowest idle RPM" and the AD deals with "core ice" problems, I still think BA38 could have had some ice build-up, enough to make the engines "hesitate".
Furthermore this AD claims to be issued to lower the risk of both engine shutdowns, but all it does, is lowering the visibility range, where pilots should/shall do "Run-ups" from 1000meters to 300meters in freezing precipitation.
This is very strange, since the renowned Norwegian Meteorologist Åsmund Rabbe already in 1999 revealed his findings: "That ice danger goes UP by factor 100 when visibility, in freezing precipitation, increases from freezing fog to freezing rain, this due to droplet size." (if bigger, far worse)
Maybe the "timing" of this AD (six days after) was just accidental, but to start doing far less "Run-ups" has earlier resulted in engines being damaged by ice (on the ground and in the air) at Oslo Gardermoen 14. dec. 1998 (20 engines) and at Denver Airport in 2002 (15 engines)
Oluf