The Bureau of Air Safety Investigation recommends that Kendell
Airlines note the circumstances of the above occurrence and alert
their aircrew accordingly.
The Bureau of Air Safety Investigation simultaneously issues this
interim recommendation to Hazelton Airlines, Macair and the Civil
Aviation Safety Authority as IR980270, IR980271 and IR980272
respectively.
The Bureau also issues related interim recommendations IR980273 and
IR980274 to the Saab Aircraft AB.
The company has taken the following action:
The sequence has been flown in the simulator and under certain
circumstances the Sim will stall at approx. 150 kts with the
necessary stall warning indications. The aircraft has the potential
to stall WITHOUT these warnings
2. The next two Sim sessions will have some element of icing
problems and an exercise involving unusual altitudes.
3.The particular aircraft has been test flown by [a company
pilot] and C.A.S.A. with various stalling configurations and the
aircraft performed normally to AFM criteria.
4.BASI have compiled a video of the incident and after some
fine-tuning we will be scheduling ALL crew to view this video as a
learning tool. It will also be included in future courses.
5.The holding pattern speed for SAAB has been increased to 170
kts in the interim. New speed data cards are to be supplied which
will indicate two VHOLD speeds
(a)Min speed when holding in icing conditions - 170 kts (less than
+ 50 in cloud)
(b)Min speed when holding in non-icing conditions will remain at
the present Vp clean speed.
6. More emphasis will be placed during training on icing
considerations and speed management when holding. It is obvious
that when holding power MUST be increased when initiating the turn
to ensure that speed does not decay below VHOLD.
7.SAAB speeds are now to be considered as MINIMUM speeds when
holding.
8.A recommendation was issued to all turbo prop manufactures to
include in their manuals the order to disconnect the autopilot when
holding in icing conditions. This in now Kendell Airlines policy
for the SAAB. "When holding in icing conditions the autopilot is to
disengaged and the procedure is to be hand flown".
9.There is still some debate regarding the effectiveness of the
deicing boots in the continuous mode due to the possibility of
"bridging". If you consider the ice build up to be excessive do no
hesitate to use the auto cycle system to give maximum protection.
"This applies to Metro and SAAB".
Monitoring all aspects of aircraft performance is important.
When operating in icing or potential icing conditions it is
"CRITICAL" that both crew monitor the aircraft performance and
operation at ALL times.
