5 Aircraft Maintenance Check Phases & How Often These Happen

Aircraft maintenance can take hours to weeks, depending on the check type. But under special programs like LUMP, inspections may be less frequent, depending on how often the aircraft flies. So, how much time does it take to maintain an aircraft? 

Citation Maintenance deals exclusively with Cessna Citation 500 series aircraft (500/501/550/551/560). Our highly skilled technicians ensure that every Citation aircraft receives the care and attention it needs to remain in top condition.

5 Phases of Citation 500 Series Inspections

Aircraft maintenance includes structured inspections that are grouped into five distinct phases. These phases ensure long-term airworthiness and safety by addressing different maintenance intervals and inspection depths. 

Phase 1 Inspection: General Inspections & Operational Checks

Frequency: Every 150 or 300 flight hours, or every 24 calendar months, whichever comes first

Phase 1 is the first level in the phased inspection schedule. It includes essential checks to keep your aircraft performing efficiently. This check covers:

• Check air cycle machine oil levels and inspect emergency lighting.
• Inspect cabin structure, door seals, windows, and steps for wear or damage.
• Perform operational tests on systems like the cockpit voice recorder, flap motor, and emergency lights.
• Inspect and test the overvoltage protection system and door warning system.
• Verify radome bonding and moisture drain holes for any blockage or damage.
• Conduct general cockpit controls and interior fittings inspection including trim tabs and control wheels.

The Citation Maintenance team works diligently to ensure Phase 1 checks are done thoroughly and efficiently to detect wear before it leads to larger problems.

Phase 2 Inspection: Flight Control & Landing Gear Checks

Frequency: Every 150 or 300 flight hours, or every 24 calendar months, whichever comes first

Phase 2 continues the sequence and covers a different set of components from Phase 1. It ensures balanced coverage over the entire aircraft by checking:

• Inspect ailerons, rudders, elevators, and trim tabs for condition and free play.
• Lubricate all major flight control actuators and trim mechanisms.
• Inspect main and nose landing gear assemblies, brakes, and tires.
• Check landing gear uplocks, actuators, and torque links for proper operation.
• Test shimmy damper, spin-up control (for gravel runways), and hydraulic functions.
• Inspect flaps, horizontal and vertical stabilizers, and associated moving parts.

Citation Maintenance provides seamless Phase 2 inspections with minimal downtime for Citation 500 operators.

Phase 3 Inspection: System Fluids & Structure

Frequency: Every 150 or 300 flight hours, or every 24 calendar months, whichever comes first

Phase 3 continues the phased program with new inspection items and lets cumulative coverage of all systems over time.

• Check air cycle machine oil and hydraulic system panels.
• Inspect humidity regulator in the air system.
• Verify all exterior moisture drain holes are clear and free from debris.
• Ensure system integrity for air, fluid, and environmental systems as applicable.
• Focus on leak detection and structural soundness in hard-to-see areas.

We ensure your Citation 500 stays in top condition through meticulous Phase 3 inspections.

Phase 4 Inspection: Engine Systems, Environmental & Thrust Reversers

Frequency: Every 150 or 300 flight hours, or every 24 calendar months, whichever comes first

Phase 4 wraps up the standard phased inspection rotation. It’s typically done alongside other phases in one scheduled visit. This phase covers:

• Perform operational tests on engine bleed air, pressurization, and deice systems.
• Inspect thrust reverser (TR) assemblies, pivot points, and guide rods (lubrication included).
• Check engine igniters, starter-generator brushes, and the generator system.
• Replace bleed air peri-seals and inspect connectors for leaks or damage.
• Conduct full engine inspections, including environmental components and pneumatic systems.

Our expert team at Citation Maintenance handles all four phases together for faster turnaround and thorough results.

Note: Under LUMP, this inspection may be extended to every 36 months if the aircraft qualifies. (This also applies to phase 1, phase 2, and phase 3)

Phase 5 Inspection: Cabin, Environmental & Bleed Systems

Frequency: Every 36 calendar months or every 1,200 flight hours, whichever comes first.

Phase 5 is the most in-depth of all the phases and includes critical checks of the aircraft’s long-term health and major components. This check covers the following:

• Inspect all aircraft placards and decals for readability and placement.
• Perform operational checks of the entire environmental control system.
• Check flow control valves and tailcone bleed air lines for leaks.
• Focus on systems that manage cabin pressure, temperature, and airflow.
• Ensure interior conditions are safe and functioning under all flight conditions.

At Citation Maintenance, our Phase 5 inspections help extend the life of your Citation 500 and ensure long-term airworthiness.

What If You Don’t Fly Often? Benefit from LUMP

Operators who fly their aircraft less frequently can benefit from a Low Utilization Maintenance Program (LUMP). This program allows longer intervals between inspections without compromising safety.

Under LUMP:

• Phase 1–4 inspections can be extended from every 24 months to every 36 months (3 years)..
• Phase 5 inspections can be extended from every 36 months to every 72 months (6 years).

This option is popular among Citation 500 series owners who use their aircraft sparingly and help reduce downtime and maintenance costs.

Citation Maintenance supports operators enrolled in LUMP by making sure every inspection meets regulatory standards even under extended intervals.

Why Does Aircraft Maintenance Take Time?

Aircraft maintenance is not a quick fix but a careful process that ensures every plane is safe to fly. Some checks take only a few hours, while major inspections can last weeks. Why does it take so long, though? 

1. Safety Regulations

Aviation authorities like the FAA and EASA have set strict safety rules that aircraft must follow. Technicians use a checklist to complete each maintenance task, ensuring nothing is overlooked.

If an issue arises, technicians must resolve it before clearing the aircraft for flight. This attention to detail takes time but is vital for passenger safety.

2. Getting it Right the First Time

There’s nothing worse than releasing an aircraft back to service only to have it return with a new problem.  Our #1 goal is to perform high quality work that meets our customers’ expectations the first time.  

3. Availability of Spare Parts

Sometimes, an inspection reveals a worn-out part that needs replacing.  The experts at Citation Maintenance are very skilled at locating serviceable parts to keep your jet in the air at a reasonable cost.  We utilize both new and used serviceable parts.  

Need Reliable Aircraft Maintenance?

Citation Maintenance is your reliable choice for expert aircraft maintenance services. Whether you need routine checks or major overhauls, we ensure your aircraft stays in top condition. People Also Ask

1. How Long Do Phase Inspections Take?

We plan 2 weeks for a phase 1-4 inspection and 3 weeks for a phase 1-5 inspection. 

2. How expensive is aircraft maintenance?

Our shop endeavors to be reasonable in our charges to our clients.  As aircraft owners ourselves we know how it feels to be at the mercy of a maintenance facility.  Our shop rate is $120 per hour and our phase inspections are priced competitively.  We can afford to do this because our location provides for low overhead.  We are focused on providing your aircraft and you with high quality service at affordable prices.  We will never hold your aircraft or logbooks hostage.

4. Who performs aircraft maintenance?

FAA certified A&P mechanics with IA complete all aircraft maintenance in accordance with aircraft, engine, and component maintenance manuals.