# Proposed AD FAA-2007-0290: Sandel Avionics Incorporated Model ST3400 Terrain Awareness Warning System/Radio Magnetic Indicator (TAWS/ RMI) Units Approved Under Technical Standard Order(s) C113, C151a, or C151b; Installed on Various Small and Transport Category Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-16-18 R1
- Products: Sandel Avionics
- Product type: Appliance
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 13, 2008, 73 FR 13498
- Comments due: April 28, 2008
- Became: [AD 2006-16-18 R1](https://openairdocs.org/ad/2006-16-18-R1)
- Docket: FAA-2007-0290 (https://www.regulations.gov/docket/FAA-2007-0290, where comments are filed)
- Project: 2007-NM-250-AD
- FR document: E8-5001
- Official PDF: https://openairdocs.org/files/sha256/5a/88/5a8836018b60129620cc708d14dff6710ae0c9804c9ed267ede95de0ba0eb0ca (from https://www.govinfo.gov/content/pkg/FR-2008-03-13/pdf/E8-5001.pdf)
- Federal Register: https://www.federalregister.gov/documents/2008/03/13/E8-5001/airworthiness-directives-sandel-avionics-incorporated-model-st3400-terrain-awareness-warning
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/994859C5EF14631E8625740C004CE401.0001
- Page: https://openairdocs.org/proposed/FAA-2007-0290

## Summary

The FAA proposes to revise an existing airworthiness directive (AD) that applies to Sandel Avionics Incorporated Model ST3400 TAWS/RMI units as described above. The existing AD currently requires installing a warning placard on the TAWS/RMI and revising the Limitations section of the airplane flight manual (AFM). The existing AD also requires installing upgraded software in the TAWS/RMI. This proposed AD would allow installing later revisions of the software described in the existing AD. This proposed AD results from a report that an in-flight bearing error occurred in a Model ST3400 TAWS/RMI configured to receive bearing information from a very high frequency omnidirectional range (VOR) receiver interface via a composite video signal, due to a combination of input signal fault and software error. We are proposing this AD to prevent a bearing error, which could lead to an airplane departing from its scheduled flight path, which could result in a reduction in separation from, and a possible collision with, other aircraft or terrain.

## Notices in this docket

- Mar 13, 2008: Notice of proposed rulemaking (NPRM). (first notice), FR document E8-5001, comments due Apr 28, 2008 (https://www.federalregister.gov/documents/2008/03/13/E8-5001/airworthiness-directives-sandel-avionics-incorporated-model-st3400-terrain-awareness-warning)

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