An inspection authority (ia) rated technician reports the air intake filter assembly with landing li...

Narrative:

The air intake filter assembly with landing light departed aircraft in flight. The bolt was found in its original hole location; the muffler assembly prevented it from moving. The bolt was secured with assembly with elastic nut plate. Threads showed evidence of proper tightening; no rust on threads. Aircraft sat dormant for a few months. No provisions for safety wire of bolt inside nose cowling. Backfire might have caused the elastic stop nut to fail; throwing the assembly into propeller and damaging left-hand side cowling fiberglass. Pilots reported pattern work; improper leaning of mixture and/or throttle jocking could have caused the backfire; a lean mixture and/or carburetor heat; maybe sudden throttle movements. Fiberglass a metal tab into nose cowl to secure a drilled head bolt; or an alternate means of safety wire for filter assembly attach bolt. Check security to filter assembly every pre-flight.

Original NASA ASRS Text

Title: An Inspection Authority (IA) Rated Technician reports the air intake filter assembly with landing light departed a Piper-28 aircraft in flight. Backfire may have caused an elastic stop nut to fail; throwing the assembly into propeller and damaging left side cowling fiberglass.

Narrative: The air intake filter assembly with landing light departed aircraft in flight. The bolt was found in its original hole location; the muffler assembly prevented it from moving. The bolt was secured with assembly with elastic nut plate. Threads showed evidence of proper tightening; no rust on threads. Aircraft sat dormant for a few months. No provisions for safety wire of bolt inside nose cowling. Backfire might have caused the elastic stop nut to fail; throwing the assembly into propeller and damaging left-hand side cowling fiberglass. Pilots reported pattern work; improper leaning of mixture and/or throttle jocking could have caused the backfire; a lean mixture and/or carburetor heat; maybe sudden throttle movements. Fiberglass a metal tab into nose cowl to secure a drilled head bolt; or an alternate means of safety wire for filter assembly attach bolt. Check security to filter assembly every pre-flight.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	882499
Time
Date	201003
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Component
Aircraft Component	Landing Light
Person 1
Function	Technician
Qualification	Maintenance Inspection Authority Maintenance Airframe Maintenance Powerplant
Experience	Maintenance Technician 35
Events
Anomaly	Aircraft Equipment Problem Critical Inflight Event / Encounter Object

An inspection authority (ia) rated technician reports the air intake filter assembly with landing light departed a piper-28 aircraft in flight. Backfire may have caused an elastic stop nut to fail; throwing the assembly into propeller and damaging left side cowling fiberglass.