Aircraft don't stay airworthy by accident. Every flight hour creates wear, every cycle stresses structure and systems, and every environment — salt air, desert dust, de-icing fluid — leaves a mark. Proper maintenance is the disciplined process that keeps that wear from becoming a failure.

This guide covers why maintenance matters, how often it must be done, and the regulations that make it law.

Why Proper Maintenance Is Non-Negotiable

Safety is the first line, not the last. Around 80% of aviation accidents have contributing maintenance or inspection factors when procedures are skipped or deferred. A properly maintained aircraft tolerates failures gracefully; a neglected one doesn't.
Reliability and dispatch. Airlines live on dispatch reliability. One AOG (Aircraft on Ground) due to a missed inspection can cancel dozens of flights and strand hundreds of passengers.
Cost. A $200 borescope inspection today can prevent a $2M engine removal tomorrow. Preventive maintenance is 3–10x cheaper than corrective repair.
Regulatory and legal airworthiness. Without signed maintenance releases, an aircraft is legally unairworthy — even if it looks perfect. No release = no flight.
Asset value. Complete, traceable maintenance records are the aircraft's logbook of trust. Missing records can slash resale value by 10–20%.

How Often Should Maintenance Be Done?

Aviation uses layered intervals — from hours to years. The exact tasks come from the manufacturer's Maintenance Planning Document (MPD) and Maintenance Review Board Report (MRBR), approved under the operator's maintenance program.

1. Pre-Flight and Daily

Pre-flight / Transit check: Pilot or mechanic walk-around before every flight — tires, fluids, controls, obvious damage.
Daily / Overnight check: At the end of a flying day — fluid levels, tire wear, lights, emergency equipment, logbook review.

2. Line Maintenance (A-Check)

Interval: Every 400–600 flight hours or 200–300 cycles, roughly every 6–8 weeks. Often done overnight in a hangar.
What: Lubrication, filter changes, operational checks, minor defect rectification. 20–50 man-hours, no heavy disassembly.

3. Base Maintenance

C-Check: Every 18–24 months or 3,000–6,000 hours. Aircraft stripped, panels opened, structures inspected, corrosion treated, engines and landing gear inspected in depth. Weeks in a hangar, thousands of man-hours.
D-Check (Heavy Maintenance Visit): Every 6–10 years or ~20,000–30,000 hours. The aircraft is essentially disassembled — paint removed, cabin out, wings and fuselage inspected rivet by rivet. Can take 25,000–50,000 man-hours and a month or more. After a D-check, the aircraft is effectively zero-timed structurally.

4. Calendar and Condition-Based Tasks

Calendar items: Life-limited parts (e.g., emergency batteries, fire bottles), corrosion prevention, calendar-driven ADs.
Condition monitoring: Engine trend monitoring (EGT margin, vibration), oil analysis, and health monitoring drive on-condition work before a limit is hit.

Rule of thumb for operators: If it flies, it’s on a clock — hours, cycles, and calendar days. The most restrictive limit wins.

The Regulations Behind Every Task

Aircraft maintenance is not optional best practice; it’s law, enforced in layers.

ICAO — The Global Baseline

ICAO Annex 6 and Annex 8 set the worldwide standard: aircraft must be maintained under an approved program, by approved organizations, with release-to-service by licensed personnel.

FAA (United States) — 14 CFR

Part 43: Who may perform and approve maintenance and how.
Part 65: Certification of mechanics and repairmen (Airframe & Powerplant).
Part 91.403–91.417: Owner/operator responsibility to maintain airworthiness, comply with ADs, and keep records.
Part 121 / 135 / 145: Additional rules for airlines and repair stations; requirement for Continuous Airworthiness Maintenance Programs (CAMP) and FAA-approved maintenance programs.
Airworthiness Directives (ADs): Legally enforceable orders — comply or ground the aircraft.

EASA (Europe) — Part-M / Part-145 / Part-66

Part-M (now Part-ML / Part-CAMO): Continuing airworthiness management.
Part-145: Approved Maintenance Organisations (AMO) — facilities, tooling, and manpower standards.
Part-66: Aircraft Maintenance Licence (AML) categories B1/B2/C — who can sign what.

Other authorities (UK CAA, TCCA, JCAB, etc.) mirror ICAO/FAA/EASA with local differences — but the principle is identical: no approved data, no approved person, no flight.

Records Are the Law

Regulations require retention of:

Total time-in-service, life-limited part status, AD compliance, and major repair/alteration data (often until the aircraft is scrapped)
Last annual/100-hour and progressive inspections (typically 12–24 months minimum)
All maintenance releases and CRS (Certificate of Release to Service)

Digital or paper, they must be complete, attributable, legible, and traceable — the same audit rigor you practice in AircraftSimulator's inventory.

What a Proper Program Looks Like in Practice

Approved Maintenance Program (AMP) tailored from the MPD/MRBR for your operation.
Work packaging — bundling tasks into checks so hangar time is minimized.
Tool control and calibration — every torque wrench, borescope, and test set tracked and calibrated; FOD control is mandatory.
Human factors — shift handovers, independent inspections for flight controls and engines, and fatigue management.
Documentation — work cards signed, CRS issued, logbook entries made, and records archived.

How AircraftSimulator Helps

AircraftSimulator was built to train this discipline without risking a real airframe:

3D interactive aircraft lets you locate and inspect systems exactly where they live.
Fault injection across electrical, fuel, hydraulic, avionics, and engine ATAs mirrors real discrepancies.
Workshop inventory enforces tool control, checkout, and audit history — just like a Part-145 tool crib.

Practice the loop on the ground so you execute it flawlessly in the hangar.

Bottom Line

Proper plane maintenance isn’t just “every 100 hours” — it’s a continuous, regulated system of daily vigilance, scheduled checks, and heavy visits, all under ICAO/FAA/EASA law. Do it on time, with approved data, approved tooling, and approved people, and aircraft remain safe, legal, and valuable for decades.

Want to practice? Open the simulator, inject a fault, and work the checklist — then track the tools you used in inventory.

Further reading: FAA AC 20-77 (Maintenance Program), EASA AMC M.A.302, ICAO Doc 9760 (Airworthiness Manual).

Aviation Maintenance Blog

The Importance of Proper Plane Maintenance: How Often, Why It Matters, and the Rules That Govern It