Aviation safety issues and actions

Maintenance processes for drain line heater

Issue number: AO-2008-003-SI-04
Who it affects: Operators of Boeing 747-400 aircraft
Issue owner: Boeing Co
Transport function: Aviation: Maintenance
Background: Investigation Report AO-2008-003
Issue release date: 13 December 2010
Current issue status: Adequately addressed
Issue status justification:

The ATSB is satisfied that, when completed, the actions being undertaken will adequately address the safety issue.

Safety issue description

Maintenance processes did not identify or correct the inoperability of the forward drain line heater.

Proactive Action

Action number: AO-2008-003-NSA-032
Action organisation: Boeing Co
Date: 13 December 2010
Action status: Closed
The aircraft manufacturer initiated a review of continuing maintenance of 747-400 drain system and ribbon heaters.

ATSB comment:

The ATSB is satisfied that the action taken by the aircraft manufacturer adequately addresses the safety issue.

Proactive Action

Action number: AO-2008-003-NSA-033
Action organisation: Qantas Airways
Date: 13 December 2010
Action status: Closed

The aircraft operator:

  • conducted a fleet inspection of 747-400 drain mast heaters, drain line heaters and drain mast hoses, and of 30 aircraft inspected, identified 11 failed drain ribbon heaters and four split drain hoses
  • performed fleet-wide drain mast heater inspections on 747-300 aircraft, and identified one failed drain ribbon heater of four aircraft inspected
  • increased the frequency of forward drain mast ribbon heater checks to every A-check. Results of the inspections will be analysed and an appropriate check interval will be established into the system of maintenance in accordance with the findings.

ATSB comment:

The ATSB is satisfied that the actions taken by the aircraft operator adequately address the safety issue.

Last update 07 March 2014