What is Scheduled and Unscheduled Aircraft Maintenance?

Introduction:

All aircraft should periodically inspect and maintain in airworthy condition to be safe to fly. Some of that maintenance is pre-scheduled. Other types of maintenance are sudden and unscheduled.

Scheduled maintenance:

Aircraft scheduled maintenance is preventative maintenance that is performed at regular intervals. This type of maintenance based on maintenance program regular checks / inspection and these intervals can be determined based on maintenance program planning method, we can categorize scheduled aircraft maintenance to:

1. Line maintenance like:
• ALC (After Landing Check).
• PDC (Pre-Departure Check).
• DC (Daily Check).
• WC (Weekly Check)
• Any other check doesn’t need hangar and could be performed as line maintenance.
2. Hangar maintenance like:
• Heavy Checks.
• Progressive inspections.
• Aircraft weighing or any other maintenance activity need hangar to be performed.

Unscheduled Maintenance:

Unlike the scheduled aircraft maintenance, the unscheduled aircraft maintenance occurs anytime a component / unit has malfunctioned or is suspected of malfunctioning, and by definition, this maintenance is unforeseen.

What are reasons for unscheduled maintenance?

The reasons of unscheduled aircraft maintenance are such:

• Pilot or maintenance staff finds a problem during the preflight inspection.
• An in-flight malfunction.
• Problems found during scheduled inspections / check.

How to minimize fleet unscheduled maintenance?

As business wise, aircraft operator aims to decrease the unscheduled maintenance to minimum this can be achieved by:

1. Effective reliability program.
2. Experienced RCB (Reliability control board) take the right decisions and follow up to measure the effectiveness and feedback.
3. Update maintenance program according to operator utilization, special operation past unscheduled maintenance study, occurrence reports study and reliability to minimize fleet unscheduled maintenance.