# SDR 99ZZZX1374

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 9, 1999
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: [N111KK](https://openairdocs.org/aircraft/N111KK), registered now
- Make and model: Lear 35A
- Registry model: [Lear 35A](https://openairdocs.org/model/gates-learjet-35a) (OpenAirDocs)
- Aircraft serial: 425
- System (JASC): [5297 · Door System Wiring](https://openairdocs.org/jasc/5297)
- Part: Wire
- Condition: Broken
- Location: Latch Pin Switch
- Part time: 7,338 hours
- Stage of operation: IN
- How discovered: C
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/99ZZZX1374

## Discrepancy

WHILE C/W LEARJET SB 35/36-52-10 (UPPER CABIN DOOR TORSION BAR ARM ASSEMBLIES); IT WAS FOUND THAT THE SHEATHING AND ALL THE WIRES INSIDE IT WERE BROKEN.  THESE WIRES ARE FOR THE UPPER DOOR LATCH PIN SWITCHES.  ACCORDING TO CHAPTER 52-10-10, PAGE 3 OF THE LEARJET 35 WIRING MANUAL, THESE SWITCHES GIVE A GROUND TO THE DOOR UNSAFE LIGHT.  WITH THESE WIRES BROKEN, THERE WOULD BE NO LIGHT EVEN WITH THE 2 CENTER LATCH PINS NOT LATCHED.  THIS FAILURE WAS CAUSED BY REPETITIVE CABIN DOOR OPENING AND CLOSING.

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