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Output Number
IR19990153
Approval Date
Published Date Time
Recommendation type
Interim recommendation
Mode
Aviation
Date released

The Bureau of Air Safety Investigation recommends that Raytheon
Aircraft consider the incorporation of an audible warning to
operate in conjunction with the cabin altitude alert system on all
Beech aircraft so equipped.



As a result of the investigation into this safety deficiency, the
Bureau simultaneously issues the following interim
recommendations:



IR19990150



The Bureau of Air Safety Investigation recommends that Raytheon
Aircraft develop and publish methods for the in-situ testing of the
automatically deployable passenger oxygen activation system and the
cabin altitude alert system on Beechcraft aircraft, to ensure
complete system operation.



IR19990151



The Bureau of Air Safety Investigation recommends that the Civil
Aviation Safety Authority reassess the appropriateness of the
current maintenance procedures for the testing of automatically
deployable passenger oxygen systems and cabin altitude alert
systems, to ensure complete system operation.



IR19990152



The Bureau of Air Safety Investigation recommends that the Federal
Aviation Administration reassess the appropriateness of the current
maintenance procedures for the testing of automatically deployable
passenger oxygen systems and cabin altitude alert systems, to
ensure complete system operation.



IR19990154



The Bureau of Air Safety Investigation recommends that the Civil
Aviation Safety Authority consider the incorporation of an audible
warning to operate in conjunction with the cabin altitude alert
system on Beech aircraft, and other aircraft so equipped.



IR19990155



The Bureau of Air Safety Investigation recommends that the Federal
Aviation Administration consider the incorporation of an audible
warning to operate in conjunction with the cabin altitude alert
system on Beech aircraft, and other aircraft so equipped.

Organisation Response
Date Received
Organisation
Raytheon Aircraft
Response Text

The 200 Series King Air's Annunciator system consists of a
warning annunciator panel with red readouts in the center of the
glareshield. Two red master warning flashers are located in the
glareshield, one in front of the pilot and one in front of the
co-pilot. The altitude warning annunciator triggers the master
warning system.



The annunciators are the "word readout" type. Whenever a fault
condition covered by the annunciator system occurs, a signal is
generated and the appropriate annunciator is illuminated. If the
fault requires the immediate attention and reaction of the pilot,
the appropriate red warning annunciator in the warning annunciator
panel illuminates and both master warning flashers begin flashing.
Any illuminated lens in the warning annunciator panel will remain
on until the fault is corrected.



Therefore, in the case of the subject incident, even though the
pressurization system was not turned on, the pilot would have been
presented with a red flashing light and a red "ALT WARN" when the
cabin altitude exceeded 12,500 feet. These two warnings are more
than adequate and meet the certification requirements of the Model
B200. There are over 1,600 Model 200 King Airs in operation
worldwide with this system installed. Raytheon Aircraft does not
believe it is necessary to add aural warning to an already proven
visual system.