MSG-3 Maintenance Steering Group

Maintenance Steering Group-3 (MSG-3) is a method for developing preventive maintenance programs in the aerospace industry. The process is maintained by A4A (Airlines For America formerly known as ATA).

MSG-3 is a structured process for identifying Safety Significant Items (SSI), defining for each SSI the failure modes and effects (FMEA). A decision tree is then applied to decide the maintenance strategy for each SSI.

Leading aircraft manufacturers use BQR’s MSG-3 software.



  • Quick and accurate analysis
  • Data is organized and maintained in one software rather than many excel sheets


BQR’s apmOptimizer software helps to organize the MSG-3 tasks and reports.

One of the MSG-3 decision trees (screenshot)

Steps for conducting MSG-3 analysis


Import (optional)

  • Import the block tree, components and failure modes from BQR’s FMECA using BQR’s Core Database
  • Alternately, data can be imported from CSV files


User Input

  • For each item, follow the decision trees according to MSG-3 forms



  • The software validates the user data. If data is missing, user is notified



  • Detailed reports for all MSG-3 forms
Detailed reports


  • Libraries for functions, malfunctions, explanations and more
  • Import tree from Excel or BQR CARE
  • Notify user if project data is incomplete or inconsistent
  • Detailed help and wizard for beginners and advanced users