The Australian Transport Safety Bureau recommends that the UK
Civil Aviation Authority ensure the adequacy of the maintenance
requirements for calibration, functional test and return to service
of barometric pressure switches used to activate cabin altitude
alerting systems in low capacity pressurised aircraft engaged in
the carriage of fare paying passengers and type certificated in the
United Kingdom.
The UK CAA has identified two aircraft types in the category of
low capacity pressurised aircraft engaged in the carriage of fare
paying passengers and type certificated in the UK: these are the
HS125 series aircraft and the BAe Jetstream family. Responsibility
for the design and manufacture of the HS125 series aircraft was
transferred from the UK to the USA on 1 st August 1995. ATSB has
confirmed that the Jetstream was the aircraft sampled in its
investigation and that, tile ATS-D considers that the Jetstream has
adequate maintenance procedures.
As a general statement, it is UK CAA policy that UK registered
aircraft be regularly flight tested in accordance with BCAR Section
A or B as appropriate, Sub-section 3-5 (Flight Testing for Renewal
of Certificates of Airworthiness or Permits to Fly). Aircraft are
tested in accordance with airworthiness flight test schedules for
the type and where appropriate these include functional testing of
the cabin low pressure warning system and passenger oxygen mask
deployment. This policy of periodic flight testing provides UK CAA
with a direct means of monitoring and if necessary improving the
effectiveness of the continued airworthiness system.
It is therefore concluded that no further action is required from
the UK CAA in respect of this Safety Recommendation.
