AD 81-20-04 R1
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 727-200 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-100 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-200 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-200C Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-300 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-400 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-500 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-600 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-700 Series | BOEING Model 727-200 and 737 Airplanes |
| aircraft | The Boeing Company | 737-800 Series | BOEING Model 727-200 and 737 Airplanes |
Unsafe Condition
Inflight fires can occur due to the use of Hamilton Standard electronic pressurization controllers with HS part numbers 710204-7, 710204-8, 761260-7, or 761260-8 that have not been modified to HS reference P57.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Modify the Hamilton Standard pressurization controllers listed in the AD by following Boeing Service Bulletins 727-21 A96 or 737-21 A1064, or an FAA-approved alternative. The Assurance of Serviceability testing from Hamilton Standard Service Bulletin 21-88, Rev 1 may substitute for the full functional test in the Boeing bulletins.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
on or before May 12, 1982
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Affected Aircraft
Boeing Model 727-200 series and 737 airplanes using Hamilton Standard pressurization controllers with HS part numbers 710204-7, 710204-8, 761260-7, or 761260-8 that have not been modified to HS reference P57.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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