SAIB AIR-22-02

FAA Aviation Safety

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN SUBJ: PITOT/STATIC ANTI-ICE SYSTEM SAIB: AIR-22-02 Date: 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

1. All BD-100-1A10 (Challenger 350) operators determine if either suspected probe part number is installed on their aircraft.

2. 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.

3. 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.

4. 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