# SAIB NM-12-25: Auto Flight: Altitude Controller

- Type: Special airworthiness information bulletin (advisory, not mandatory)
- Status: Current
- Revision: 0
- Issued: April 16, 2012
- Products: Hawker Beechcraft 400, 400A and 60
- Product type: Aircraft, Large Airplane
- PDF: https://openairdocs.org/files/sha256/f9/07/f90755ce227685e9b9f6485ccfed0ed31dc0b3623e084d6de20728e7495ca2cf
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9DF546528D596494862579E2006F2F0F.0001
- DRS record last changed: April 16, 2012
- Page: https://openairdocs.org/saib/NM-12-25

## Text

FAA Aviation Safety

**SPECIAL AIRWORTHINESS**

INFORMATION BULLETIN SAIB: NM-12-25 SUBJ: Auto Flight: Altitude Controller Date: April 16, 2012 This is information only. Recommendations aren’t mandatory.

Introduction This Special Airworthiness Information Bulletin (SAIB) advises registered owners and operators of Hawker Beechcraft Corporation (type certificate previously held by Raytheon Aircraft Company; Beech Aircraft Corporation) Model 400 and 400A airplanes, and Learjet Inc. Model 60 airplanes of failure of certain 115VAC power transients in the following Rockwell Collins units:

AAP-850 ALTITUDE AWARENESS PANEL (CPN 622-7398-001/002); and AAP-851 ALTITUDE AWARENESS PANEL (CPN 822-0328-001/002/003/004/011/012/013/014).

Background Rockwell Collins has analyzed the failure of several AAP-851 units associated with smoke in the cockpit incidents for the subject airplanes. The cause was determined to be a varistor protection device.

Rockwell Collins issued Service Bulletin AAP-850/851-34-3, dated January 18, 2012, to provide operators with guidelines for removing the varistor from the AAP-851 and AAP-850 and replacing it with a sufficiently de-rated protection device.

In evaluating the design of the AAP-850/-851 panels, Rockwell Collins determined that all materials are self-extinguishing and do not pose a fire hazard. Based on this design evaluation, as well as the actual events that prompted this SAIB, the amount of smoke produced is not significant.

Additionally, the loss of function for the altitude awareness panel does not prevent continued safe flight and landing.

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 Aviation Regulations (14 CFR) part 39.

Recommendations The FAA recommends that all owners and operators of the subject airplanes comply with the guidelines outlined in Rockwell Collins Service Bulletin AAP-850/851-34-3, dated January 18, 2012, for all applicable part numbers/serial numbers of AAP-850 and AAP-851 units.

For Further Information Contact Roger A. Souter, Aerospace Engineer, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Wichita, KS 67209; phone: (316) 946-4134, fax: (316) 946-4107, e-mail:

roger.souter@faa.gov.

For Related Service Information Contact Rockwell Collins, Inc., 400 Collins Road NE., MS 153-150, Cedar Rapids, Iowa 52498;

phone 319-295-1000; fax 319-295-4941; e-mail response@rockwellcollins.com;

Internet http://www.rockwellcollins.com.

## Registered aircraft it may concern (OpenAirDocs)

Registry models matched by make and model, the same way as ADs, most registered aircraft first.

- [Learjet 60](https://openairdocs.org/model/learjet-60): 237 registered aircraft (airframe model)
- [Raytheon 400A](https://openairdocs.org/model/raytheon-400a): 216 registered aircraft (airframe model)
- [Beech 400A](https://openairdocs.org/model/beech-400a): 43 registered aircraft (airframe model)
- [Hawker Beechcraft 400A](https://openairdocs.org/model/hawker-beechcraft-400a): 39 registered aircraft (airframe model)
- [Beech 60](https://openairdocs.org/model/beech-60): 32 registered aircraft (airframe model)
- [Learjet 60 XR](https://openairdocs.org/model/learjet-60-xr): 2 registered aircraft (airframe model)

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