Aviation safety investigations & reports

Flight control system event involving Embraer 120, VH-YEI, Adelaide Airport, SA, on 25 October 2016

Investigation number:
AO-2016-143
Status: Completed
Investigation completed

Final Report

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On 25 October 2016, at about 0640 Central Daylight-saving Time, an Embraer-120 ER aircraft, registered VH-YEI (YEI), departed from Adelaide Airport, South Australia, for a chartered passenger flight to Challenger, SA with 4 crew and 29 passengers on board.

During climb, the pilot attempted to fully retract the flaps (flaps 0) from their take-off position (flaps 15). The crew received a flap disagreement warning from the outboard pair of flaps. After deciding to return to Adelaide, the crew determined that they had sufficient runway to land with flaps 15, in case they could not be deployed further. During approach, the flaps fully extended (flaps 45) and the aircraft landed without further incident. There were no injuries as a result of the occurrence.

Inspection of the aircraft revealed that pre-existing cracking and subsequent fracture of a bracket supporting the left, outboard flap shroud prevented the flap from retracting during climb, resulting in the flap disagreement warning. No problems with the flap shroud or bracket were identified during maintenance inspections. However, the maintainer believes that the location of the bracket would make it difficult to see any cracks during line checks and daily inspections.

Following the identification of the failed bracket, the operator inspected similar parts on YEI as well as the rest of their Embraer-120 fleet. No further damage was identified.

This incident highlights the importance of comprehensive maintenance inspections in maintaining aircraft airworthiness. However, when technical failures occur in spite of rigorous maintenance procedures, it is important to have adequate risk controls in place, as well as trained crew capable of adjusting plans to account for unforeseen circumstances. In such an event, a positive outcome can be achieved by keeping composure, planning ahead, and maintaining communication.

Part of Aviation Short Investigations Bulletin - Issue 60

Download final report
[Download  PDF: 198KB]
 
 
Alternate: [Download  DOCX: 921KB]
 

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General details
Date: 25 October 2016   Investigation status: Completed  
Time: 06:40 CSuT    
Location   (show map): Adelaide Airport   Investigation type: Occurrence Investigation  
State: South Australia   Occurrence type: Flight control systems  
Release date: 24 May 2017   Occurrence class: Operational  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Embraer-Empresa Brasileira De Aeronautica  
Aircraft model EMB-120 ER  
Aircraft registration VH-YEI  
Serial number 120.269  
Type of operation Charter  
Sector Turboprop  
Damage to aircraft Nil  
Departure point Adelaide, SA  
Destination Challenger, SA  
Last update 14 November 2018