You walk into your hangar and your mechanic gives you the news. Your Cessna 172 needs a new part. Maybe it's a cylinder that's lost compression. Maybe your starter finally gave up. You ask for the price and your stomach drops.

Here's the thing about aircraft parts. They cost a lot more than car parts. A lot more. And when you own a 172, you're going to need parts sooner or later. Every pilot who owns a plane faces this moment.

So you start looking around. You see used parts online. You hear about overhauled parts from other pilots at the airport. The prices look way better. But a little voice in your head asks: Is this safe? Will my airplane stay in the air with a used part on it?

You're asking the right question. The average aircraft owner spends between $10,000 and $30,000 per year on maintenance. That's a big chunk of money, and finding safe ways to save makes sense.

The good news is that many used and overhauled parts are perfectly safe for your 172. The trick is knowing which ones to buy and which ones to avoid. You also need to know what paperwork protects you and what red flags mean "walk away."

This post goes over everything you need to know about buying used vs overhauled parts on a 172 so you can keep your plane flying safely without emptying your bank account.

Key Takeaways

Not all used or overhauled parts are created equal. Some parts like control cables, avionics, and properly overhauled engines are safe to buy used when they come with the right documentation (especially FAA Form 8130-3). Other parts like filters, gaskets, cylinders, and anything without proper paperwork should always be purchased new. The key is understanding which category each part falls into, verifying all documentation, working with certified suppliers, and consulting your A&P mechanic before making any purchase. PMA (Parts Manufacturer Approval) parts offer a middle ground—they're new, FAA-approved, and cost 30-70% less than OEM parts while meeting identical safety standards.

Why 172 Parts Cost So Much (And Why That Makes Used Parts Tempting)

You need a new alternator for your car. You go to the auto parts store and pay maybe $150. Now you need an alternator for your Cessna 172. Same basic part. Similar function. The price? Try $800 or more.

Why the huge difference?

Aviation parts live in a different world than car parts. Every single part that goes on a certified aircraft needs approval from the FAA. The company making that part has to prove it meets strict safety standards. They run tests. They document everything. They keep detailed records of every part they make.

All that work costs money. And you pay for it.

Here's what drives up the cost:

• Certification requirements - Companies spend thousands of hours getting FAA approval for each part
• Traceability - Every part needs a paper trail showing where it came from and who made it
• Testing standards - Parts get tested beyond what car parts face because lives depend on them
• Liability - If a part fails in flight, the manufacturer faces huge legal risks
• Lower production volume - They make millions of car alternators but only thousands of aircraft alternators

Your 172 probably has a Lycoming O-320 or O-360 engine. A factory new engine from Lycoming costs around $45,000 to $55,000. An engine overhaul runs $28,000 to $38,000. That's serious money for most owners.

Even small parts add up fast. A set of four new cylinders? Around $5,000. A prop overhaul? Another $3,000 to $5,000. Exhaust system? $2,500 and up.

Now you see why used and overhauled parts look so tempting. A good overhauled starter might cost $600 instead of $1,200. Used avionics can save you 50% or more. PMA parts (we'll explain these later) often cost 30-70% less than original parts.

But here's the big question: Can you trust these cheaper options?

The answer is yes, but only if you know what to look for. Some parts are perfectly safe to buy used. Others could put you and your passengers at risk. The difference comes down to understanding what you're buying.

The Three Types of Parts You'll Find for Sale

When you start shopping for parts, you'll see different terms thrown around. Let's clear up what each one means.

Brand New OEM Parts

OEM stands for Original Equipment Manufacturer. For your 172, that's Cessna (now owned by Textron Aviation). These parts are brand new, straight from the factory. They come with all the right paperwork. They're also the most expensive option.

Think of OEM parts as buying name-brand medicine. You know exactly what you're getting.

PMA Parts

PMA means Parts Manufacturer Approval. These are new parts made by companies other than Cessna. But here's the important part: The FAA approves these manufacturers to make parts that meet the exact same standards as OEM parts.

Companies like McFarlane Aviation and Preferred Airparts make thousands of PMA parts for Cessnas. Same quality, same safety, lower price. We'll dig deeper into PMA parts later because they're a smart way to save money.

Overhauled or Rebuilt Parts

These parts started their life on another airplane. When they reached the end of their service life, a certified repair shop took them apart, inspected every piece, replaced worn parts, and put them back together to meet FAA standards.

A properly overhauled part can be just as reliable as new. The key word is "properly." You need to make sure a certified shop did the work and can prove it with paperwork.

Used Serviceable Parts

These parts came off another aircraft but still have useful life left. Maybe a plane got upgraded to new avionics, so the old ones got removed. They worked fine—they just got replaced for other reasons.

Think of it like buying a used car part from a junkyard. Sometimes you get a great deal. Sometimes you get problems. The difference is that aviation has stricter rules about what paperwork these parts need.

The Parts You Must Avoid

You'll also run into parts with no documentation. Parts from eBay sellers who can't prove where they came from. Parts that look good but have no paper trail.

Stay away from these. Your mechanic can't legally install them. And even if they could, you don't want mystery parts keeping your plane in the air.

Understanding these categories helps you shop smart. You can save money without cutting corners on safety.

What "Airworthy" Really Means for Your Safety

You'll hear the word "airworthy" a lot when shopping for parts. It sounds official, but what does it actually mean?

Airworthy means a part meets FAA safety standards and is legal to install on your aircraft. Your mechanic has to certify that every part going on your plane is airworthy. If they can't, they won't install it. It's that simple.

Your Mechanic's License Is On the Line

Here's something important to understand. When your A&P (Airframe and Powerplant) mechanic signs off on work, they're putting their license at risk. If they install a bad part and something goes wrong, the FAA can take away their ability to work on planes.

That's why good mechanics are picky about parts. They're not trying to make your life difficult. They're protecting you and themselves.

The Inspection That Matters

Before any part goes on your plane, your mechanic does an inspection. They check that:

• The part number matches what your plane needs
• The part has the right documentation
• There's no visible damage or wear
• The part meets current FAA requirements

Even a brand new part gets inspected. Even a part from Cessna. Your mechanic checks everything.

Documentation Makes It Legal

A part can look perfect and still not be airworthy. Why? No paperwork.

The FAA requires a paper trail showing:

• Who made the part
• When it was made or overhauled
• That it meets approved standards
• That it's been properly stored and handled

This isn't busy work. This checklist protects everyone. If a part fails and causes an accident, investigators trace that part back to find out what went wrong. Good documentation helps prevent future failures.

What Happens Without Proper Documentation

Let's say you find a starter for $300 on eBay. No paperwork included. Your mechanic says they can't install it.

You might think: "But it looks fine. Can't we just try it?"

No. Here's why:

• Your plane's airworthiness certificate depends on all parts being legal
• Insurance might not cover an accident if unapproved parts were installed
• You could face FAA fines
• The plane could be grounded until the part is removed
• You've now wasted $300 plus the downtime and labor to remove it

The TBO Factor

Some parts have something called TBO - Time Between Overhaul. For engines, this is usually around 2,000 hours for most Lycoming engines (though the 180 hp versions might vary).

TBO tells you when a part should be inspected, overhauled, or replaced. It's not always a hard limit for Part 91 operations (that's the rule set for most private pilots). But it's a strong guideline.

When you buy a rebuilt engine or overhauled part, you need to know:

• How much time is on it since the last overhaul
• How much time is left before the next one
• Whether all required inspections were done

This affects the part's value and how long you can use it before spending more money.

What Airworthy Really Comes Down To

At the end of the day, airworthy means: This part is safe, it's legal, and we can prove it. That's the standard you should hold every part to. Buy the cheapest parts you want, but never skip the airworthy requirement.

Your life depends on it. Your passengers depend on it. And honestly, your wallet depends on it too—because fixing problems from bad parts costs way more than buying the right ones the first time.

Safe Parts to Buy Used or Overhauled for Your Cessna 172

You want to save money, but you want to stay safe. Here are the parts where used or overhauled options make sense—and the ones where they don't.

Engine Parts: Know What Works and What Doesn't

Safe to Buy Overhauled:

Your engine is the most expensive part of your airplane. When it needs work, the bills get big fast. A complete engine overhaul from a reputable shop can save you $15,000 to $20,000 compared to a factory new engine.

Here's what you can safely buy overhauled:

• Complete overhauled engines - Look for shops with strong reputations and good warranties. Pinnacle Aircraft Engines, Ly-Con, and similar certified facilities do quality work. You'll pay $28,000 to $38,000 for an overhauled O-320, compared to $50,000+ for new. Make sure the shop is FAA-certified and provides complete documentation.
• Starter motors - These are straightforward to rebuild. A good overhauled starter runs $500 to $800 with a warranty, versus $1,500 new. They either work or they don't, making them low-risk.
• Alternators - Similar to starters. Overhauled units from certified shops come with warranties and cost about half of new. Just make sure the shop tested the output properly.
• Fuel pumps - Both mechanical and electric fuel pumps can be overhauled safely. Verify the shop pressure-tested them and included documentation.

Better to Buy New:

Some engine parts just aren't worth the risk or the savings:

• Cylinders - Here's a specific number: New cylinders cost around $1,200 each. Overhauled ones might save you $300 to $400 per cylinder, but experts consistently recommend buying new. Why? Cylinders are high-wear items. An overhauled cylinder might pass inspection but fail after 200 hours. Then you're paying for the removal, installation of a new one, plus the downtime. Buy new cylinders and sleep better.
• Crankshafts - The Lycoming O-320 engines (common in older 172s) have hollow crankshafts. These collect sludge and corrosive material inside over years of use. You can't see this damage from the outside. Many crankshafts fail inspection during overhaul. A new crankshaft costs $3,800 to $6,500. If you're doing an engine overhaul, plan for a new crank unless yours is very low time.
• Pistons and rings - These wear over time. The cost savings on used ones is minimal, but the risk of early failure is high. Just buy new.
• Gaskets and seals - Always new. Every time. These are cheap insurance against leaks.

What About Run-Out Engines?

Sometimes you'll see "run-out" engines for sale. These are engines at or past their TBO that still run. They're cheap—maybe $5,000 to $10,000.

Should you buy one? Only if you're planning an immediate overhaul and want to save on a core exchange. Never install a run-out engine and just hope it keeps running. That's gambling with your life.

Airframe Parts That Are Usually Safe Used

Your airframe has hundreds of parts. Many are perfectly safe to buy used when properly inspected.

Good Candidates for Used Parts:

• Control cables - Cables for throttle, mixture, and flight controls can be bought used if they show no fraying, cracks, or corrosion. Your mechanic should inspect them carefully. PMA companies like McFarlane make excellent new cables for less than OEM prices, though. That's often the smarter choice.
• Seat rails and brackets - These are sturdy parts that rarely wear out. Used ones from a salvage yard work fine if they're straight and undamaged. Check for cracks where torque loads occur.
• Landing gear components - Struts, axles, and wheels can be purchased used. But get them inspected for cracks and proper torque specifications. Any sign of damage means walk away.
• Interior plastic panels - Headliners, sidewalls, and instrument covers are safe used purchases. They're not structural or safety-critical.
• Rudder pedals and linkages - These are simple mechanical parts that last decades if treated well.

What Requires Extra Caution:

• Engine mounts - These can be bought used, but they need careful inspection. Look for cracks near weld joints. Even tiny cracks can grow under stress. Many mechanics recommend new mounts because the cost difference isn't huge compared to the safety risk.
• Exhaust systems - Here's the tricky part about exhausts: They rust from the inside out. A used exhaust might look perfect on the outside but be dangerously thin inside. Internal corrosion causes leaks that can let carbon monoxide into the cabin. If you buy used, insist on an internal inspection or borescope check.

Avionics: The Tricky Middle Ground

Used avionics represent a huge opportunity to save money. A new Garmin GPS can cost $8,000 to $15,000. A used one might be $4,000 to $7,000.

What Works:

• GPS navigators - Garmin 430s, 530s, and other popular units change hands regularly. Make sure the manufacturer still supports them with database updates and repairs.
• Audio panels - These are fairly simple and reliable. Used ones from known brands work well.
• Transponders - Older transponders work fine if they meet current ADS-B requirements (if needed in your airspace).
• Radios - Comm and nav radios are safe to buy used from aircraft avionics shops that test and certify them.

What to Watch Out For:

Some avionics manufacturers stop supporting older models. Garmin discontinued repairs for certain GPS units built before 2000. If you buy one of these and it breaks, you can't get it fixed. Check with the manufacturer about support status before buying any used avionics.

Also verify that the unit is approved for your specific 172 model and year. Not all avionics work in all planes.

Parts You Should Never Buy Used

Some parts should always come out of a box marked "new." The risk isn't worth the savings.

The Never-Ever List

Consumable Parts:

These parts are designed for one-time use or limited life. Always replace them new:

• Oil filters - Cost: $15 to $30. Why risk it?
• Air filters - Same logic. New ones are cheap.
• Fuel filters - Critical for keeping your engine running. Don't gamble.
• Gaskets - Once compressed, they don't seal as well. Always new.
• O-rings - These cost pennies. Buy new every time.
• Safety wire and cotter pins - These are one-use items. Your mechanic should have fresh supplies.
• Spark plugs - While you can clean and regap them, new ones cost $15 to $30 each. For reliability, buy new.

High-Risk Structural Items:

• Wing spars - The main structural beam of the wing should never be purchased used unless it comes from a certified salvage operation with complete documentation and inspection. Even then, most mechanics won't touch used spars.
• Bulkheads - Structural frames in the fuselage. Too critical for used.
• Landing gear struts (in some cases) - If they show any damage, cracks, or corrosion, walk away.

Anything Past Shelf Life:

Some products have expiration dates:

• Adhesives and sealants - These lose effectiveness over time
• Paints and primers - Old paint won't protect properly
• Certain lubricants - Check expiration dates
• Rubber components - Hoses, boots, and seals degrade with age even if unused

Understanding Life-Limited Parts

Life-limited parts have a hard expiration measured in flight hours, cycles (takeoffs and landings), or calendar time. When they hit that limit, they must be replaced. No exceptions.

In engines, life-limited parts include certain gears, bearings, and rotating components. The FAA requires complete documentation showing the part's history from birth to current state.

If you buy a life-limited part, you need:

• Original manufacturer paperwork
• Every overhaul and inspection record
• Current hours/cycles remaining
• Complete chain of custody

Missing any of this? The part is worthless. You can't prove its history, so you can't legally use it.

Most Cessna 172 owners won't buy individual life-limited parts—they come as part of an engine overhaul. But if you're piecing together an engine rebuild, pay close attention to this.

The Paperwork That Protects You

Let's go over the documents that make a part legal to install on your aircraft.

FAA Form 8130-3: Your Safety Shield

Form 8130-3 is called an Airworthiness Approval Tag. Think of it as a birth certificate for aircraft parts.

This form proves:

• The part was made under FAA approval
• It meets required standards
• It's been properly maintained or overhauled
• It's traceable to a certified source

Only certain people can issue this form:

• FAA-certified manufacturers
• Part 145 certified repair stations
• Airlines with maintenance programs
• Designated Airworthiness Representatives (DARs)

When you buy a used or overhauled part, ask for the 8130-3. If the seller can't provide it, walk away. No form means no proof the part is airworthy.

Other Documentation You Need

Certificate of Conformance (CoC):

New parts from manufacturers come with a CoC. This certifies the part was built correctly and matches approved specifications. It's similar to the 8130-3 but applies to brand new production parts.

Maintenance Records:

For overhauled parts, you need records showing:

• Who did the overhaul
• When it was done
• What work was performed
• What replacement parts were used
• Test results after the work

A reputable overhaul shop provides detailed records. If they won't, find another shop.

Work Orders from Repair Shops:

Certified repair stations issue work orders describing the work performed. These documents support the 8130-3 and prove the shop's certification.

Red Flags in Documentation

Watch out for:

• Handwritten forms (8130-3s should be typed or computer-generated)
• Missing signatures or dates
• Parts from sources that don't match the documentation
• Copies without originals available
• Documentation that looks altered or forged

If something feels off, it probably is. Trust your gut and ask your mechanic to verify documents before buying.

What Your Mechanic Needs

Before installation, your mechanic verifies:

• The part number matches your airplane's requirements
• Documentation proves airworthiness
• The part hasn't been altered improperly
• All required inspections are current
• The part meets current FAA Airworthiness Directives (ADs)

Without proper paperwork, your mechanic can't do their job. Save yourself time and money by getting the documentation right from the start.

PMA Parts: The Secret to Smart Savings

Here's one of the best-kept secrets in aviation: You don't have to buy parts from Cessna to get safe, reliable parts for your Cessna 172.

What PMA Really Means

PMA stands for Parts Manufacturer Approval. Companies apply to the FAA for permission to manufacture parts that replace original equipment. The FAA puts them through rigorous testing to prove the parts meet or exceed OEM standards.

Once approved, these manufacturers can legally make replacement parts for your airplane.

Why PMA Parts Are Just as Safe as OEM

Here's what many pilots don't realize: PMA parts must pass the same tests as original parts. The FAA doesn't give PMA approval to inferior products.

In fact, PMA parts often improve on the original design. Why? Because PMA manufacturers can't just copy the old design—they often have to reverse-engineer it or create new designs that perform the same function. This leads to innovation.

For example:

• McFarlane Aviation redesigned control cables with better corrosion resistance
• Some PMA manufacturers use stronger materials than the original parts
• Modern manufacturing techniques often produce tighter tolerances

The 2011 FAA Part 21 revision removed most legal distinctions between OEM and PMA manufacturing. The FAA views them as equally valid.

Real-World Savings

Let's look at actual numbers:

• OEM control cable: $180
  PMA control cable: $95
  Savings: 47%
• OEM engine baffles: $450
  PMA engine baffles: $180
  Savings: 60%
• OEM brake parts: $320
  PMA brake parts: $125
  Savings: 61%

Over the life of your aircraft, PMA parts can save you thousands of dollars.

Trusted PMA Manufacturers

Some PMA companies have built strong reputations:

• McFarlane Aviation - Known for control cables, seat rails, and numerous airframe parts
• Preferred Airparts - Large inventory of PMA parts with same-day shipping
• Air Research Technology - Makes STOL modification kits
• Rapco - Brake components and other mechanical parts

These companies have been in business for decades. They stand behind their products. Many offer warranties that match or exceed OEM coverage.

Debunking the Myths

Myth: "PMA parts are cheaper because they're lower quality."
 Reality: They're cheaper because PMA manufacturers have lower overhead and more competition. Quality standards are identical.

Myth: "Using PMA parts voids your warranty."
 Reality: The FAA and insurance companies cannot discriminate against approved PMA parts. If someone tells you this, they're wrong.

Myth: "Mechanics don't like working with PMA parts."
 Reality: Good mechanics care about proper documentation and quality. If a PMA part has both, they have no issue installing it.

When to Choose PMA

PMA parts make sense for:

• Routine maintenance items that need regular replacement
• Airframe parts like cables, brackets, and hardware
• Parts where the OEM charges premium prices
• Situations where you want proven improvements over original designs

When OEM Might Be Better

Sometimes OEM parts make more sense:

• Complex assemblies where fit is critical
• If you're selling the airplane soon and buyers specifically want all-OEM parts
• When PMA options simply don't exist for that part
• If the price difference is minimal

The bottom line: PMA parts give you safe, legal options to save money without compromising safety.

How to Spot Sketchy Parts and Bad Deals

You're going to run into sellers who cut corners. Here's how to spot them before you waste money or compromise safety.

Warning Signs to Watch For

No Documentation:

If a seller says "it's a good part, trust me" but can't provide Form 8130-3 or other paperwork, run away. Every legitimate aircraft part has a paper trail.

eBay and General Marketplaces:

eBay has some legitimate aviation parts sellers. But it also has people selling parts from their barn with no certification, no traceability, and no accountability. Unless the seller is a known aviation business with proper credentials, be very careful.

"Like New" Without Proof:

Terms like "like new," "remanufactured," or "rebuilt" mean nothing without documentation from a certified facility. Anyone can clean up a part and call it "like new."

Wrong Part Numbers:

Always verify the part number matches what your airplane needs. A prop hub from a 172N won't necessarily work on a 172S. Sellers sometimes list parts incorrectly, or they don't understand compatibility.

Missing Serial Numbers:

Many parts come with serial numbers or data plates. If these are missing, the part's history is gone. Your mechanic probably won't install it.

Price Too Good to Be True:

A Lycoming cylinder sells new for $1,200. If someone offers one for $200 with no documentation, what's the catch? Either it's stolen, it's damaged, or it's not actually airworthy.

Questions to Ask Before Buying

Can you provide the FAA Form 8130-3?

This should be an easy yes. If they hesitate or say it's not needed, move on.

What's the part's service history?

For used or overhauled parts, you need to know:

• Total time since new
• Time since last overhaul
• How many hours are left before next service
• Any damage history or repairs

Are you a certified repair station?

For overhauled parts, verify the shop has FAA Part 145 certification. Ask for their certificate number and look it up on the FAA website.

Is this part approved for my specific 172 model?

A 172M from 1976 is different from a 172S from 2005. Parts aren't always interchangeable. Get confirmation in writing that the part fits your model and year.

Does this come with any warranty?

Reputable sellers stand behind their work. New and overhauled parts should have some warranty period. If they say "no warranty, sold as-is," that's a red flag for overhauled parts.

Red Flags in Communication

Pay attention to how sellers respond:

• Vague answers - "I think it's from a 172" isn't good enough
• Pressure tactics - "Buy now or I'll sell it to someone else" suggests they're hiding something
• Unwillingness to answer questions - Legit sellers want informed buyers
• Can't provide photos - In today's world, anyone can text photos. If they won't, why not?

Checking Seller Credentials

For Repair Stations:

Visit the FAA website and search their database of certified repair stations. Verify:

• The certificate is current
• The shop is rated for the type of work they claim
• There are no enforcement actions against them

For Parts Suppliers:

Look for:

• How long they've been in business
• Reviews from other pilots
• Membership in industry groups like the Aviation Suppliers Association
• Physical address and phone number (not just email)

For Salvage Yards:

Good salvage operations:

• Have proper facilities and certifications
• Document where parts came from
• Inspect parts before selling
• Provide accurate descriptions of condition
• Stand behind their products

The Gut Check

Sometimes a deal feels wrong even if you can't point to a specific problem. Trust that feeling. Your Cessna 172 keeps you alive. Don't risk it on a questionable part to save a few hundred dollars.

The best deals come from established suppliers with good reputations. You might pay slightly more, but you get peace of mind and proper support.

Different 172 Models Need Different Parts

Here's something that trips up a lot of buyers: Not all 172s are the same. A part from a 1975 model might not fit a 2005 model.

Why Your Model Year Matters

Cessna built the 172 for decades. Over that time, they made changes:

1963-1967 (172D through 172H):

• Continental O-300 engines (6-cylinder)
• Different instrument panels
• Unique landing gear geometry

1968-1976 (172I through 172M):

• Switched to Lycoming O-320 engines (4-cylinder)
• Different prop requirements
• Changes to fuel systems

1977-1986 (172N and 172P):

• Updated electrical systems
• Different avionics mounting
• Modified engine baffling

1996-present (172R and 172S):

• Fuel-injected IO-360 engines
• Corrosion-proofed at factory
• Modern avionics from factory
• Completely different electrical architecture

The 172R vs 172S Difference:

Even these look similar but have critical differences:

• 172R: 160 hp (derated from 180 hp engine)
• 172S: Full 180 hp
• Different props and engine baffling
• Some avionics are model-specific

What to Verify Before Ordering

Your Exact Model Letter:

Your airplane's data plate shows the model. It might say:

• 172M
• 172N
• 172P
• 172R
• 172S

That letter matters. When ordering parts, give the seller this exact model designation.

Your Serial Number:

The serial number helps identify exactly when your aircraft was built and what specific configuration it has. Cessna sometimes made mid-year changes. Your serial number pinpoints your airplane.

Which Engine You Have:

Know your engine model. Common ones:

• O-300-D (older 172s)
• O-320-E2D
• O-320-H2AD
• IO-360-L2A (172R and 172S)

Parts like engine baffles, exhaust systems, and engine mounts differ between these engines.

Common Mix-Ups

Fuel Systems:

Older 172s had metal fuel tanks. Newer ones have bladder tanks. The fuel caps, sending units, and fittings are different.

Landing Gear:

The 172RG (retractable gear) uses completely different parts than fixed-gear models. Don't assume parts interchange.

Avionics Trays:

A radio tray from a 1980s 172 won't fit the panel of a G1000-equipped 172S. Measure everything and verify fitment.

Brake Systems:

Cleveland brakes are common, but the specific model varies by year. Brake discs, calipers, and master cylinders changed over the years.

How to Avoid Expensive Mistakes

Work with your mechanic:

Before ordering any expensive part, have your mechanic verify the part number. They can look in the parts manual for your specific model.

Call the supplier:

Good suppliers ask for your model and serial number before recommending parts. If they don't ask, they might not know enough to help you correctly.

Check the parts manual:

Cessna parts manuals list exactly which part numbers fit which models. Your mechanic should have access to these. Some are available online.

Look at the old part:

The part you're replacing usually has a part number stamped or labeled on it. That's your best reference for finding the correct replacement.

Special Cases

STCs (Supplemental Type Certificates):

If your airplane has modifications—like a 180 hp engine conversion, extended range fuel tanks, or STOL kits—standard parts might not work. You need parts compatible with those modifications.

Foreign-Built 172s:

Reims Aviation in France built 172s under license from Cessna. These Reims-Cessna aircraft sometimes use slightly different parts. Check compatibility carefully.

The bottom line: Take five extra minutes to verify you're ordering the right part for your specific airplane. It saves you from the hassle of returning wrong parts and the downtime of waiting for correct ones.

Conclusion

Buying used vs overhauled parts on a 172 doesn't have to be a gamble. You can save serious money and keep your airplane safe when you know what to look for.

The smart approach starts with understanding which parts are safe to buy used—things like complete engine overhauls from certified shops, control cables, and properly documented avionics. Then you avoid the never-buy-used items like consumables, cylinders, and anything missing proper paperwork.

Your protection comes from documentation, especially that FAA Form 8130-3. Without it, you're buying risk, not savings. And remember that PMA parts give you brand-new quality at used-part prices. Companies like McFarlane Aviation have proven that you don't need to pay OEM prices to get OEM safety.

Work with your mechanic as a partner. They want you to save money too, but not at the expense of safety or their license. Ask questions. Verify part numbers for your specific model. Check seller credentials. Take your time to get it right.

The aviation community includes thousands of pilots who maintain their planes smartly without breaking the bank. You can join them by making informed choices about every part you buy.

Ready to find your next aircraft or get expert guidance on aircraft ownership? Visit Flying411 for comprehensive listings, inspection checklists, and resources that help you make smart decisions about buying, selling, and maintaining your aircraft.

Frequently Asked Questions

How do I know if an overhauled engine is truly airworthy?

An airworthy overhauled engine comes from an FAA-certified Part 145 repair station that provides complete documentation including Form 8130-3, detailed work orders showing all parts replaced, test results proving proper compression and leak rates, and a logbook entry from the facility. The shop should provide a warranty and be willing to answer questions about their process. Request references from other pilots who used their services and verify the shop's certification status on the FAA website before committing.

Can I buy parts from aircraft salvage yards safely?

Yes, but only from reputable salvage operations that maintain proper documentation and inspection records. Legitimate salvage yards track where parts came from, inspect them for damage or wear, provide Form 8130-3 or equivalent paperwork, and clearly describe the part's condition and service history. Companies like Atlanta Air Exchange and Texas Air Salvage have decades of experience. Avoid salvage yards that can't provide documentation or won't answer questions about a part's history.

What's the difference between TBO and mandatory replacement for parts?

TBO (Time Between Overhaul) is a manufacturer recommendation, not a legal requirement for Part 91 operations (most private pilots). You can fly beyond TBO if your mechanic confirms the engine or part meets airworthiness standards during regular inspections. However, life-limited parts have mandatory replacement intervals that are legally required—when they reach their limit in hours or cycles, they must be replaced regardless of condition. Your mechanic and the parts manual identify which parts are life-limited.

How can I verify if a PMA part is approved for my specific Cessna 172?

Visit the FAA's PMA database online and search by part number or manufacturer name to verify current approval status. The database shows which aircraft models each PMA part is approved for. You can also contact the PMA manufacturer directly—companies like McFarlane Aviation have customer service teams that help you confirm compatibility with your specific model and year. Your mechanic can also verify PMA approval and proper installation procedures before ordering.

What should I do if my mechanic refuses to install a part I purchased?

First, ask why they're refusing—it's likely a documentation or compatibility issue, not stubbornness. Good mechanics won't install parts without proper paperwork because it puts their license at risk. If the part lacks Form 8130-3 or doesn't match your airplane's requirements, they're protecting you by refusing. Return the part if possible and buy from a certified source. If you believe your mechanic is wrong, get a second opinion from another A&P, but understand that no reputable mechanic will install questionable parts.