Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
AIR-22-02
February 25, 2022
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin is in response to the
Columbus, Ohio Flight Standards District Office (FSDO) concerns that a
large Part 135 operator has identified through their Continuing
Analysis and Surveillance System that a significant number of their
Bombardier Inc. BD-100-1A10 (Challenger 350) fleet had a high number of
occurrences of un-commanded aircraft pitot heat activation. The
aircraft pitot heat activated as soon as aircraft or ground power was
applied to the aircraft with the control panel switch for pitot heat in
the OFF position. In these conditions, the aircrew have no awareness
that heat is being applied to the pitot probe. The aircraft Crew
Alerting System (CAS) is not designed to identify an un-commanded pitot
heat activation due to an internally shorted pitot probe.
At this time, the airworthiness concern is not an unsafe condition that
would warrant airworthiness directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) part 39.
Background
The affected pitot probe part numbers are 0856WC3 and 0856WC4. When
these pitot probe parts fail they short to ground and this is the ON
configuration. Currently Bombardier Inc. cannot offer a pitot tube part
number for the BD-100-1A10 (Challenger 350) that is proven not to fail
in the ON configuration when the probe internally fails and shorts to
ground. The pitot heat system plays an extremely important role in the
safe operation and airworthiness of the aircraft particularly when
operating in icing conditions and at the altitudes that the aircraft
routinely operates.
Recommendations
All BD-100-1A10 (Challenger 350) operators determine if either suspected probe part number is installed on their aircraft.
If a suspect probe part
number is installed, check to see if the pitot heat is ON with the
pitot heat switch in the OFF position each time and anytime while ship
power or ground power is applied to the aircraft.
If pitot probe heat comes ON
with the pitot probe heat switch in the OFF position, the operator
should replace the probe as soon as possible.
Bombardier issue a Service
Bulletin that will address and properly correct the un-commanded
operation of the pitot probe heat circuit.
Bombardier Inc Advisory Wire
Pitot-Static Heater, AW300-30-0082 Rev 2, dated February 21, 2020
addresses items 1. through 3. in this Safety Recommendation. This SAIB
recommends that Bombardier Inc. BD-100-1A10 (Challenger 350) operators
perform the actions in this Advisory Wire.
Transport Canada Civil Aviation (TCCA) has been notified of this
condition. TCCA has been requested to work with Bombardier Inc. to come
up with a Service Bulletin to address item 4.
For Further Information Contact
Thomas Niczky, Aerospace Engineer, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590, United States; phone: (516) 228-7347; fax: (516)
794-5531; e-mail: Thomas.W.Niczky@faa.gov.
(Optional) For Related Service Information Contact
Bombardier Inc. 400 Côte-Vertu Road West Dorval, Québec, H4S 1Y9 Canada Phone 1-866-538-1247