EMBRAER EMB-145LR near Chicago, IL — 2010-03-13

Probable cause

An in-flight encounter with lightning. Contributing to the incident was the damaged and displaced tailcone bulkhead frame that inhibited the full travel of the elevator during approach.

Contributing factors

Contributing to the incident was the damaged and displaced tailcone bulkhead frame that inhibited the full travel of the elevator during approach.

NTSB narrative

The airplane received minor damage when it sustained a lightning strike while on approach. The flightcrew subsequently encountered elevator control binding, although they were able to land without further incident. Both flightcrew members indicated that the control yoke could be manipulated in the aft direction, but that it would not move forward past about 60-percent deflection. A postaccident inspection of the airplane revealed that the tailcone was damaged. Examination of the damage disclosed that the tailcone's light assembly wiring harness and its respective overbraid shielding were thermally damaged. A bulkhead frame was dislodged from its location due to the thermal damage present on the wiring harness. The dislodged bulkhead came to rest on the elevator's bellcrank, which restricted the flightcrew's ability to control the elevator. Subsequent to the incident, the airplane's manufacturer redesigned the tailcone. The new design incorporates a light assembly secured to the tip of the tailcone by an aluminum retaining strap. In this design four diverters are installed on the exterior tailcone skin which are electrically bonded to the metallic retaining strap of the light assembly and to the metallic bonding plate installed in each side of the fairing.

Analysis

Primary failure mode

Mechanical failure

First missed decision gate

Crew could have opted to divert to avoid lightning in the area.

NTSB coding

• Flight control sys malf/fail · Approach-IFR final approach

Evidence available

• FDR / data
• Photos
• 9 docket documents

Docket documents9

• Flight Data Recorder 10 - Attachment 1 - Tabular Datafdr
• Flight Data Recorder 10 - Specialist's Factual Reportfdr
• Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1form
• Flightcrew Statementsinterview
• Statement of Party Representatives to NTSB Investigationinterview
• ROYKO Approach Chartother
• Photo 1 - View of the rear portion of the tailcone and its displaced light assembly.photos
• Systems 9 - Factual Report of Group Chairman (with 18 embedded photos)photos
• Meteorology 5 - Factual Report of Group Chairmanreport