AD 91-09-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 737-300 Series | Airworthiness Directives; BOEING Model 737-300, 737-400, and 737-500 Series Airplanes |
| aircraft | The Boeing Company | 737-400 Series | Airworthiness Directives; BOEING Model 737-300, 737-400, and 737-500 Series Airplanes |
| aircraft | The Boeing Company | 737-500 Series | Airworthiness Directives; BOEING Model 737-300, 737-400, and 737-500 Series Airplanes |
Unsafe Condition
Cross connection of the engine fire extinguishing wiring and plumbing during maintenance could lead to failure of the fire extinguishing system.
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Required Actions
Accomplish modifications per Boeing Service Bulletin 737-26-1067 for applicable airplanes. Terminate repetitive inspections and functional tests required by AD 89-03-51 for airplanes with PRR 34774 modification. Obtain alternative compliance with FAA approval.
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Compliance Time
within the next 36 months after the effective date of this AD, unless previously accomplished
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Affected Aircraft
All Model 737-300, 737-400, and 737-500 series airplanes, certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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