AD 74-23-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 727-100 Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727-100C Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727-200 Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727-200F Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727 Series | BOEING Model 727 Series Airplanes |
| aircraft | The Boeing Company | 727C Series | BOEING Model 727 Series Airplanes |
Unsafe Condition
Inadvertent trip of both air conditioning packs leading to rapid loss of cabin pressurization.
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Required Actions
Within one calendar day after the effective date, control the Auto Pack Trip System using Boeing Operations Manual Bulletin 74-7. Within 100 hours time in service, collar the Auto Pack Trip circuit breaker on P6 panel and install placards. Within 900 hours time in service, modify the system per specified Boeing Service Bulletins or approved method.
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Compliance Time
Effective November 8, 1974. Actions required within one calendar day, 100 hours time in service, and 900 hours time in service after effective date.
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Affected Aircraft
Boeing Model 727 Series airplanes with Auto Pack Trip System, including 727-100, 727-100C, 727-200, 727-200F series, specific serial ranges as listed in the referenced service bulletins.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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