# STC SA155RM

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Learjet Inc, United States
- Description: Installation of Singer SKK-1000 doppler navigation system, SKQ-601 dead reckoning computer, and Sperry C-12 compass system.
- Applied: September 22, 1978
- Status date: March 7, 2002
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 2A4](https://openairdocs.org/tcds/2A4)
- Certificate PDF: https://openairdocs.org/files/sha256/33/53/335316ed34d4d4b9b8e1fd09afc2f3f0aa965e478987b759b0b405a40825bfad
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D3004E2B1E3C344585256CC100821353.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA155RM

## ADs that name it (0)

None.

## Approved models (1)

- Twin Commander Aircraft Corporation 685 ([TCDS 2A4](https://openairdocs.org/tcds/2A4))

## What the certificate says

This is OCR from the scanned FAA certificate. OCR can misread letters and numbers.

Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA155RM This certificate issued to: Learjet Inc.

One Learjet Way Wichita, KS 67209 Certifies that the change in the type design for the following product with the limitations and condition's therefer as specified hereen meets the airverthiness requirement's of Part. 3 of the Civil Air Regulations.

Original Product -Type Terlificate Number: 2A4 Make: Rockwell Commander Model: 685 Description of Type Design Change:

Installation of Singer SKK-1000 Doppler Navigation System, SKQ-601 Dead Reckoning Computer, and Sperry C-12 Compass System in accordance with Avionics Engineering of Denver Drawing List and installation instructions specified on sealed FAA Forms 8110-3 dated September 23, 1978, and September 25, 1978 or later approved revision.

A placard must be installed on the pilot's instrument panel which states: "USE OF DOPPLER NAVIGATION SYSTEM LIMITED TO VFR ONLY."

This approval should not be extended to other aircraft of this model on which previously approved modifications are incorporated unless it is determined by the installer that the interrelationship between this change and any of these other previously approved modifications will introduce no adverse effect upon the airworthiness of the aircraft.

Date of Application: September 22, 1978 Date Reissued: January 4, 1995, March 7, 2002 Date of Issuance: October 4, 1978 Date Amended:

FEDERAL AVIATION By Direction of the Administrator David T. Grossman (Signature) Acting Manager *OMINIST RATION Northwest Mountain Region, Denver, Colorado Denver Aircraft Certification Office.

(Title)

47.

## Every issue (1)

- March 7, 2002: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/33/53/335316ed34d4d4b9b8e1fd09afc2f3f0aa965e478987b759b0b405a40825bfad)

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