AD 2010-20-12
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | Company Model 747-400 | Airworthiness Directives; The Boeing Company Model 747-400, 747-400D, and 747-400F Series Airplanes |
Unsafe Condition
An electrical hot short from a source outside the fuel quantity indicating system (FQIS) to the densitometer wiring can cause failure of the FQIS densitometer resistors, resulting in an ignition source inside the center or horizontal stabilizer fuel tanks. An ignition source combined with flammable fuel vapors could cause a fuel tank explosion and loss of the airplane.
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Required Actions
Install a hot short protector (HSP) for the FQIS of the center fuel tank and, for certain airplanes, the horizontal stabilizer fuel tank according to the service bulletins. Use Boeing Service Bulletin 747-28A2266, Revision 1 and Alert Service Bulletin 747-28A2267 as applicable.
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Compliance Time
Within the compliance times specified in the AD, which is effective November 5, 2010.
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Affected Aircraft
The Boeing Company Model 747-400, 747-400D, and 747-400F series airplanes certificated in any category, as identified in Boeing Service Bulletins 747-28A2266 (Rev 1) and 747-28A2267.
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Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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