SAIB AIR-21-15

FAA Aviation Safety

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN SUBJ: Navigation System SAIB: AIR-21-15 Date: August 26, 2021 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises owners and operators of 328 Support Services GmbH Model 328-100 and -300 airplanes; Learjet, Inc., Model 45 airplanes; Yaborã Indústria Aeronáutica S.A. Model EMB-135ER, EMB-135LR, EMB-135BJ (Legacy 600), EMB-135KE, EMB-135BJ (Legacy 650), EMB-135KL, EMB-145, -145ER, -145MR, -145LR, - 145XR, -145MP, and -145EP airplanes; Textron Aviation Inc. Model 500 550 S550 552 560 and 560XL airplanes, Model 501 and 551 airplanes, Model 650 airplanes, and Model Hawker 800 (including variant U-125A), 800XP, and 1000 airplanes; Bombardier, Inc., Model CL-600-1A11

(600), CL-600-2A12 (601), and CL-600-2B16 (601-3A, 601-3R, and 604 Variants) airplanes;

Bombardier, Inc., Model BD-700-1A10, BD-700-1A11, and BD-700-2A12 airplanes; Viking Air Limited Model CL-215-6B11 (CL-415 Variant) airplanes; and Textron Aviation, Inc., Model 750 airplanes; having a Honeywell Primus II Radio System with Radio Management Unit (RMU) 855 installed, of the potential for inadvertent disabling of the Automatic Dependent Surveillance – Broadcast (ADS-B) Out function.

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 FAA received reports in January and February 2020 of ADS-B Out compliant aircraft on which ADS-B Out transmissions were not operating. The cause of this was due to certain avionics power up sequences involving the RMU-855. The crew could be unaware of this issue unless informed of it by Air Traffic Control (ATC). Honeywell has identified different airplanes with this equipment, totaling approximately 2,750 affected airplanes. This condition results in failure to comply with 14 CFR

91.225 and 14 CFR 91.227 when ADS-B Out is disabled and the aircraft operates in the airspace defined in 14 CFR 91.225.

Honeywell Service Bulletin 7013270-34-0024, dated December 19, 2019, and Honeywell Service Information Letter D201507000061, Revision 4, dated April 6, 2021, have been issued to provide procedures for ensuring power up sequencing in the integrated radio system, and accomplishing a software update at authorized repair stations.

Recommendations

The FAA recommends that all owners and operators of the airplanes identified above incorporate the actions outlined in the referenced service information at the earliest opportunity.

2 For Further Information Contact

Charles Toliver, Aerospace Engineer, Systems and Equipment Section, Los Angeles ACO Branch, 3960 Paramount Blvd , Lakewood, CA 90712-4137, telephone: 562-627-5367; e-mail Charles.Toliver@faa.gov.