Understanding Scheduled Maintenance

Scheduled maintenance is the backbone of aircraft airworthiness. Unlike automotive maintenance where you might postpone an oil change by a few weeks, aircraft maintenance intervals are legally binding. Operating an aircraft beyond its scheduled maintenance limits is a violation of aviation regulations and can result in grounding, insurance voidance, and legal liability.

The maintenance programme for each aircraft type is defined by the manufacturer and approved by the relevant aviation authority (FAA, EASA, or national equivalent). These programmes specify which inspections, component replacements, and system checks must be performed at defined intervals. Plane Selection manages compliance tracking and coordinates all scheduled events to minimize downtime and cost.

Types of Scheduled Inspections

A Check (Light Maintenance)

An A check is a relatively light inspection performed approximately every 400-600 flight hours, depending on the aircraft type. It typically takes 1-3 days and is performed in a hangar or on the ramp. The A check includes visual inspections of the airframe, systems checks, lubrication, filter replacements, and minor component servicing.

For business jets, A checks often align with 200-hour or 300-hour inspections depending on the manufacturer. These are the most frequent scheduled events and should be planned well in advance to minimize operational disruption.

B Check (Intermediate)

B checks are performed approximately every 6-8 months and involve more detailed inspections than A checks. They typically require 1-5 days in a hangar and include functional tests of aircraft systems, structural sampling inspections, and component condition assessments. Many modern maintenance programmes have incorporated B check tasks into A and C checks, but some older aircraft types still follow the traditional A-B-C-D structure.

C Check (Heavy Maintenance)

A C check is a comprehensive inspection that takes the aircraft out of service for 2-4 weeks. Performed every 4,000-6,000 flight hours (or every 24-48 months for lower-utilization business jets), the C check involves extensive structural inspections, system tests, component overhauls, and corrosion treatment. Interior panels, floor panels, and access panels are removed to allow inspection of underlying structure.

C checks are significant events both operationally and financially. A C check on a large-cabin business jet typically costs $500,000-$1,500,000 depending on the aircraft type, age, and any additional work required. Proper planning and facility selection can significantly reduce both cost and downtime.

D Check (Major Overhaul)

The D check is the most extensive scheduled inspection, essentially disassembling and reassembling the aircraft. Performed every 8-12 years, a D check can take 2-3 months and cost $2-5 million for a business jet. The aircraft is stripped to its bare structure, every system is inspected or overhauled, corrosion is treated, and the aircraft is effectively rebuilt.

For many business jet owners, the D check is a decision point: the cost of the check versus the remaining useful life and market value of the aircraft must be weighed carefully. Plane Selection provides detailed cost-benefit analysis to help owners make informed decisions about D check investment versus aircraft replacement.

Calendar-Based Inspections

In addition to flight-hour-based checks, aircraft require calendar-based inspections regardless of how much they fly:

• 12-month inspection: Annual airworthiness review including systems functional tests, structural sampling, and regulatory compliance verification
• 24-month inspection: More comprehensive biennial inspection including pitot-static system tests, transponder certification, and ELT checks
• 48-month inspection: Extended interval inspection including landing gear detailed inspection, flight control system checks, and fuel system inspections
• 96-month inspection: Deep structural inspection including NDT (non-destructive testing) of critical structural elements

Component Life Limits

Beyond airframe inspections, individual components have their own maintenance schedules. Life-limited parts must be replaced at defined intervals regardless of condition. These include:

• Landing gear: Overhaul typically required every 10-12 years or 12,000-15,000 cycles, costing $200,000-$600,000 per set
• Wheels and brakes: Regular replacement based on wear and cycles
• Flight control actuators: Overhaul intervals of 5,000-10,000 hours
• APU (Auxiliary Power Unit): Hot section inspection and overhaul at manufacturer-defined intervals
• Oxygen system: Bottle hydrostatic testing and system checks on defined schedules
• Fire extinguisher bottles: Weight checks and hydrostatic testing per regulatory requirements

Airworthiness Directives (ADs)

Airworthiness Directives are mandatory instructions issued by aviation authorities (FAA, EASA) requiring specific inspections, modifications, or component replacements to address identified safety issues. ADs can be one-time actions or recurring inspections. Compliance with all applicable ADs is mandatory and must be documented in the aircraft's maintenance records.

Plane Selection tracks all ADs applicable to each aircraft we manage, ensures timely compliance, and coordinates the work with appropriate facilities. We also monitor service bulletins (SBs) issued by manufacturers, which while not always mandatory, often address reliability improvements that benefit the aircraft's operation and value.

Our Scheduled Maintenance Process

1. Maintenance forecasting: We build a rolling maintenance forecast for your aircraft, projecting all upcoming inspections, component life limits, and AD compliance requirements. This allows you to plan and budget months or years in advance.
2. Facility selection: For each event, we identify the optimal MRO facility based on aircraft type expertise, availability, pricing, and geographic convenience. We obtain multiple quotes and negotiate on your behalf.
3. Work scope definition: Before the aircraft enters the facility, we define a detailed work scope covering all required inspections, known discrepancies, and any discretionary work the owner wishes to address during the downtime opportunity.
4. Pre-induction coordination: We coordinate ferry flights, crew logistics, parts pre-positioning, and any special tooling requirements to ensure the maintenance event starts on schedule.
5. Progress monitoring: Throughout the event, we monitor daily progress, review findings, evaluate additional work recommendations, and keep the owner informed of status, costs, and any schedule changes.
6. Quality assurance: Before accepting the aircraft back, we verify that all work has been completed correctly, documentation is accurate, and the aircraft is in full airworthy condition.
7. Return to service: We coordinate the acceptance flight, return ferry, and any post-maintenance operational checks to ensure seamless return to normal operations.

Minimizing Downtime

Every day your aircraft is in maintenance is a day it cannot fly. We minimize downtime through careful planning, parallel work scheduling, advance parts ordering, and proactive communication with the MRO facility. Where possible, we combine multiple maintenance events to reduce total hangar time — for example, scheduling an interior refurbishment or avionics upgrade during a C check when the aircraft is already out of service.

Schedule Your Next Inspection

Contact Plane Selection to discuss your aircraft's upcoming maintenance requirements. We will review your maintenance programme, identify upcoming events, and develop a plan that keeps your aircraft compliant and minimizes disruption to your flying schedule.