Author: Mike Reynolds

Mike Reynolds is an A&P certified mechanic with over 15 years of experience in general aviation maintenance. He specializes in piston aircraft and has worked on everything from Cessna 150s to Beechcraft Bonanzas. Mike is passionate about helping aircraft owners find the right parts and maintain their planes safely.
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How to Choose the Right Oil for Your Aircraft Engine

Vintage aircraft engine with propeller

Selecting the right oil for your aircraft engine is one of the most important decisions you’ll make as an owner. The wrong choice can lead to accelerated wear, reduced engine life, and even engine failure. This guide covers everything you need to know about aviation oils.

Understanding Aviation Oil Grades

Aviation oils use a different grading system than automotive oils. You’ll see designations like W80, W100, and W120, where the “W” stands for “weight” (not “winter” as in automotive oils) and the number indicates viscosity.

Common Aviation Oil Grades

  • W80: Lighter weight, often used in cold climates or for break-in
  • W100: The most common grade for Continental and Lycoming engines
  • W120: Heavier weight for hot climates or high-time engines
  • 15W-50: Multi-viscosity, popular year-round choice

Straight Weight vs. Multi-Viscosity

The debate between single-grade and multi-viscosity oils has continued for decades. Each has advantages depending on your operating environment.

Single Grade Oils (W100, W80)

Single grade oils maintain consistent viscosity at operating temperature. Many engine manufacturers recommend single grade oils, and they’re typically required for engine break-in. They’re also generally less expensive than multi-viscosity options.

Multi-Viscosity Oils (15W-50, 20W-50)

Multi-viscosity oils provide better cold-start protection while maintaining proper viscosity at operating temperatures. They’re excellent for aircraft that operate in varying climates or see infrequent use where cold starts are common.

Mineral Oil vs. Ashless Dispersant

Mineral Oil

Straight mineral oil is required during engine break-in (typically the first 25-50 hours). It allows piston rings to properly seat against cylinder walls. Using ashless dispersant oil during break-in can prevent proper ring seating and lead to high oil consumption.

Ashless Dispersant (AD) Oil

After break-in, most aircraft transition to ashless dispersant oil. AD oils contain additives that:

  • Suspend contaminants and carry them to the oil filter
  • Reduce sludge and varnish formation
  • Provide better corrosion protection
  • Extend time between oil changes

Popular Aviation Oil Brands

AeroShell

AeroShell is the most widely used aviation oil brand worldwide. Their lineup includes:

  • AeroShell W100: Standard single-grade AD oil
  • AeroShell 15W-50: Popular multi-viscosity option
  • AeroShell 100: Mineral oil for break-in
  • AeroShell W100 Plus: Contains anti-wear additive LW-16702

Phillips 66

Phillips offers a complete line of aviation oils:

  • X/C 20W-50: Multi-viscosity AD oil
  • Type A: Single-grade AD oils
  • Victory AW: Premium anti-wear formulation

Exxon/Mobil

Exxon produces the Elite series of aviation oils, offering both single and multi-grade options with advanced additive packages.

Oil Change Intervals

Most manufacturers recommend oil changes every 50 hours or 4 months, whichever comes first. However, oil analysis can help optimize your change intervals. Factors affecting intervals include:

  • Flight frequency (more frequent flying is better)
  • Climate and operating temperatures
  • Engine condition and oil consumption
  • Oil filter type (full-flow vs. spin-on)

Oil Analysis: Your Engine’s Report Card

Regular oil analysis is one of the best investments you can make. For about $30 per sample, you get detailed information about:

  • Wear metals (iron, copper, aluminum, chrome)
  • Contamination (silicon, sodium, water)
  • Oil condition (viscosity, oxidation)

Trending this data over time reveals developing problems before they become expensive failures.

What Your Engine Manufacturer Recommends

Continental

Continental engines typically call for single-grade AD oil (W100 in most climates) after break-in. Multi-viscosity is approved but single-grade is preferred. Always consult your specific engine’s operator’s manual.

Lycoming

Lycoming approves both single and multi-viscosity AD oils after break-in. They specifically recommend their own brand (now marketed by Phillips 66) but approve equivalent products from other manufacturers.

Making Your Choice

For most aircraft owners, here’s a simple decision tree:

  1. New or overhauled engine: Use mineral oil until break-in is complete
  2. Year-round, moderate climate: W100 ashless dispersant
  3. Cold climate or infrequent flying: 15W-50 or 20W-50 multi-viscosity
  4. Hot climate or high-time engine: Consider W100 Plus or W120

When in doubt, consult your A&P mechanic. They know your engine’s history and operating conditions better than anyone. And whatever oil you choose, change it regularly—consistent maintenance is more important than brand selection.

Recommended Products

Based on our recommendations above, here are some of the most popular aviation oils and filters available. These products are trusted by aircraft owners and mechanics worldwide.

AeroShell Oil W100 Plus

The W100 Plus is an enhanced version of the classic AeroShell W100, featuring the anti-wear additive LW-16702. This additive provides extra protection against cam and lifter wear, making it an excellent choice for high-performance piston engines. Ideal for year-round use in moderate climates.

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AeroShell Oil W 15W-50

For aircraft owners who fly in varying temperatures or don’t fly as frequently, the 15W-50 multi-viscosity is an excellent choice. It provides superior cold-start protection while maintaining proper viscosity at operating temperatures. Great for seasonal flyers and those in northern climates.

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Tempest AA48110-2 Spin-On Oil Filter

Don’t forget the oil filter! The Tempest AA48110-2 is a popular spin-on replacement for many Continental and Lycoming engines. Quality filtration is essential for protecting your engine and extending oil life. Always change your filter with every oil change.

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The Complete Annual Inspection Supplies Checklist for Aircraft Owners

Aircraft maintenance inspection

Every aircraft owner knows that the annual inspection is the most important maintenance event of the year. Whether you’re preparing your Cessna, Piper, or Beechcraft for its yearly checkup, having the right supplies on hand can save time and money while ensuring your aircraft meets all airworthiness requirements.

What is an Annual Inspection?

An annual inspection is a comprehensive examination of your aircraft required by FAR 91.409. Only an IA (Inspection Authorization) holder can perform and sign off an annual inspection, though aircraft owners can assist with disassembly and reassembly under supervision. The inspection covers every system: airframe, powerplant, propeller, and all installed equipment.

Essential Supplies for Your Annual

Safety Wire and Hardware

Safety wire is critical for securing bolts, nuts, and turnbuckles throughout your aircraft. You’ll need .032″ stainless steel safety wire for most applications, along with safety wire pliers. Don’t forget cotter pins in various sizes for securing castellated nuts on control systems.

Oil and Filters

Your annual is the perfect time for an oil change. Stock up on the correct grade of aviation oil for your engine—whether that’s straight mineral oil for break-in or ashless dispersant oil for normal operation. Don’t forget a new oil filter and the proper O-ring.

Filters and Gaskets

Beyond oil filters, you may need fuel filters, air filters, and various gaskets. Inspect your gasket inventory before the annual begins. Common items include rocker cover gaskets, oil sump gaskets, and exhaust gaskets.

Spark Plugs and Ignition

While spark plugs don’t always need replacement at every annual, they do need inspection and cleaning. Have a complete set of new plugs available in case any show excessive wear or damage. Massive electrode and fine wire plugs each have their advocates.

Cleaning Supplies

A thorough annual requires a clean aircraft. Stock up on:

  • Aircraft-approved degreasers for engine cleaning
  • Aluminum-safe cleaners for airframe surfaces
  • Lint-free cloths and shop towels
  • Inspection mirrors and borescopes

Lubricants

Proper lubrication extends component life and prevents corrosion. Essential lubricants include:

  • Aeroshell 33MS grease for wheel bearings
  • LPS-2 or equivalent for control cables
  • Corrosion preventive compounds for battery terminals
  • Silicone spray for door seals and weatherstripping

Creating Your Annual Inspection Kit

Smart aircraft owners maintain a dedicated annual inspection kit. Store all your supplies together so nothing is forgotten when inspection time arrives. Replace items as they’re used throughout the year.

Recommended Kit Contents:

  1. Safety wire (.032″ and .041″)
  2. Cotter pins (assorted sizes)
  3. Oil (6 quarts minimum)
  4. Oil filter
  5. Spark plugs (full set)
  6. Fuel strainer gasket
  7. Rocker cover gaskets
  8. Degreaser and cleaners
  9. Shop towels
  10. Grease and lubricants

Working With Your IA

Communication with your IA is key to a successful annual. Discuss any squawks or concerns before the inspection begins. If you plan to assist with the work, clarify which tasks you can perform under supervision. Owner-assisted annuals can significantly reduce costs while giving you deeper knowledge of your aircraft.

Documentation

Keep records of all parts used during your annual. Serial numbers from filters, part numbers from replaced components, and lot numbers from consumables should all be documented. This information is valuable for warranty claims and helps track component life.

Plan Ahead

Don’t wait until the last minute to gather supplies. Order parts at least two weeks before your scheduled annual to account for shipping delays and potential backorders. Having everything ready when your IA arrives maximizes efficiency and minimizes aircraft downtime.

A well-prepared annual inspection protects your investment, ensures safe flight operations, and often catches small problems before they become expensive repairs. Stock your maintenance kit with quality parts and supplies, and your annual will go smoothly year after year.

Recommended Annual Inspection Supplies

Here are the essential supplies every aircraft owner should have on hand for annual inspection time. These products are trusted by A&P mechanics and aircraft owners nationwide.

Safety Wire Kit with Pliers

This complete kit includes 50 feet of .032″ stainless steel safety wire plus professional-grade safety wire pliers. The pliers feature a reversible twist mechanism for both left and right-hand applications—essential for properly securing bolts, castle nuts, and turnbuckles throughout your aircraft.

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Aviation Grade Safety Wire (1 lb Spool)

For those who go through more wire, this 1-pound spool of APP aviation-grade .032″ stainless steel safety wire meets MS20995C and ASTM A580 specifications. Made from genuine 302/304 stainless steel, this is the same quality wire used by professional maintenance shops.

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AeroShell 33 Airframe Grease

AeroShell Grease 33 is the industry-standard multipurpose airframe grease meeting MIL-PRF-23827C specifications. This 14oz cartridge is perfect for wheel bearings, control system bearings, and general airframe lubrication. Every hangar should have a tube ready for annual inspection time.

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Tempest Oil Filter Torque Wrench

The Tempest AA472 oil filter torque wrench is preset to the correct 17 ft-lbs torque specification for spin-on aviation oil filters. The 1″ hex drive fits all standard aircraft oil filters and includes a built-in torque limiter to prevent over-tightening. Essential for proper filter installation.

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Aviation Oil Filter Cutter

Cutting open your oil filter to inspect for metal contamination is a critical part of any annual inspection. This heavy-duty filter cutter cleanly opens any spin-on aviation oil filter, including Champion, Tempest, and Continental filters. Look for metal particles that could indicate internal engine wear.

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Articulating Inspection Borescope

A quality borescope allows you to inspect cylinder walls, valve seats, and other hard-to-reach areas without disassembly. This 360° articulating model features a 5-inch IPS display, 6 LED lights, and 5X zoom—ideal for engine cylinder inspections and checking for corrosion in airframe cavities.

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Champion Spark Plug REM40E

The Champion REM40E is one of the most common aviation spark plugs, fitting many Continental and Lycoming engine applications. These massive electrode plugs are known for reliability and long service life. Always have a spare set available for your annual in case any plugs show wear or damage.

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