The SAAB Operators Conference held at Clearwater Florida in October 2006 discussed recommendations A-06-48 and A-06-51 arising from the American Eagle SAAB340 event.
Rec A-06-48: Require all operators of Saab SF340 series airplane to instruct pilots to maintain a minimum operating airspeed of 1.45xVs during icing encounters and before entering known or forecast icing conditions and to exit icing conditions as soon as performance degradations prevent the airplane from maintaining 1.45xVs.
Note that the NTSB classified A-06-48 as an URGENT recommendation!
Rec A-06-51: Require all operators of turbopropeller-driven airplanes to instruct pilots, except during intermittent periods of high workload, to disengage the autopilot and fly the airplane manually when operating in icing conditions.
As stated previously, the American Eagle SAAB340 AOM called for a speec of VCLN +15 kts, which in the case of the occurrence flight, would have been VCLN 126 kts + 13 kts = 139 kts. So, with VCLN of 126 kts = 1.2 '1g' VS, the VS in that case would have been 105 kts.
Therefore, the 'icing' encounter speed according to recommendedation A-06-48 should have been 152 kts, or 13 kts greater than the speed given in the American Eagle SAAB340 AOM.
However, it seems there's some difference in opinion between SAAB and the NTSB regarding the icing 'encounter' speed.
While the NTSB are recommending to the FAA that the icing 'encounter' speed should be 1.45 VS, SAAB 'characterize the [American Eagle] event as a low speed event, and is recommending operators to follow speed information and procedures for flight in icing conditions published in the Aircraft Operations Manual.
WOW! That represents about a 9% margin between the NTSB and SAAB recommended speeds!
Under the circumstances, I reckon I know which speed I'd prefer to be flying at!
