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Posted 1 years 6 days ago ago by jhadmin

Since I received such a good response to my last article on annual inspections, I thought I’d follow up with another piece on helicopter pre-buy inspections.

Just about everything written relating to aircraft pre-buys is skewed to the plank-wing side of the industry. While similar in scope, there are several distinct differences in reviewing a helicopter before purchase.

So sit back, pop a top, and we’ll see if I can keep you awake for the next 1,500 words.


Unlike the single-engine airplane world, we don’t hear of many pre-buy horror stories in the helicopter world. But they do exist. There are several reasons for this: a different demographic in who buys a helicopter; the sheer difference in numbers of airplanes versus helicopters; and, the inherent use of more specialized or experienced personnel for the helicopter pre-buy.

Also, I structured the article to the actual pre-buy. We will assume you, the prospective buyer, have done your due diligence and selected a specific model aircraft to suit your needs and desires. But whether it’s an Airbus, Bell, Enstrom, Robinson, or Sikorsky, the tips below should keep you on the straight and narrow.


We should start with some basic terminology. Being a bit old school, I still use the term “pre-buy inspection.” Some people smarter than me point out it is better to use the label “pre-purchase evaluation.” Seems the use of “inspection” could have a legal connotation if something goes awry during or after the pre-buy.

While a poorly executed pre-buy can lead to issues—some serious—in my opinion it has nothing to do with nomenclature. Rather, it’s more the lack of a coordinated plan, or as in some cases, simply not following the rules of common sense.

Speaking of rules, there is no FAA requirement or mandated guidance when it comes to performing a pre-buy, or pre-purchase evaluation. None. A pre-buy lies somewhere between a turnaround check and a complete aircraft teardown.

So even though a pre-buy is an extremely important part of buying a helicopter, it falls to the prospective buyer—along with their mechanic and the seller—to determine the goals of the pre-buy.


My Number One pre-buy tip is to use the same mechanic or shop for the pre-buy that will maintain your new helicopter after purchase. Unfortunately, this suggestion usually falls on deaf ears.

Although most of the negative feedback I get on this tip is understandable—even reasonable—there is one important issue some folks fail to consider: the mechanic you hire in BFE to perform the pre-buy is not the one who will present you with that $10,000 repair estimate after its first annual or scheduled inspection. But… But…

But what? The BFE mechanic determined an item to be airworthy and your mechanic does not? We all know airworthy is both objective and subjective. However, rarely have I seen the same mechanic change his subjective determination of airworthiness on the same item.

By sticking with your primary maintenance provider for the pre-buy and cutting out the middleman, you can develop a working relationship or agreement with your mechanic on any issues that surface now or in the future.

Tip Number Two: once your mechanic is onboard, create the guide or checklist to use for the pre-buy. Here, you should lean heavily on the mechanic for input, while remaining integral to the entire process. After all, as the new owner you will be legally responsible for the helicopter’s airworthiness. With a pre-buy checklist decided upon, you can now format it, identify it, and print it out specifically for that helicopter.

Tip Number Three: after the pre-buy checklist is documented, send a copy to the seller for review. There may be something on the list that he doesn’t understand or refuses to allow. If the seller balks, make it a negotiating point, or work out an alternative check with your mechanic—or maybe even walk away.

Tip Number Four: get everyone’s agreement in writing. It doesn’t need to be complex or official. A simple, signed written agreement between you and your mechanic—and you and the seller—describing the who, what, when, where, and how of the pre-buy inspection will provide memory enhancement should the need arise.


The disposition of any discrepancies encountered during the pre-buy should be discussed with the seller prior to the pre-buy and the result entered in your agreement with him. This is not to protect you as much as it is to protect your mechanic.

Even though a pre-buy is not an FAA required inspection, some of the work performed during a pre-buy could fall under Part 43. For example, the mechanic checks the engine chip plugs for debris and notes a small number of flakes that have not bridged the plug gap.

Since Part 43 is a performance regulation (versus an operational regulation like Part 91) your certified A&P mechanic is required to perform maintenance in accordance with Part 43. Now, what if one of those flakes is larger than permitted by the maintenance manual, requiring further checks? Oh, boy.

The last thing a desperate seller wants to hear is that his aircraft is broke and the discrepancy needs to be documented. But then again, if you hadn’t checked the chip plugs, you could have been stuck with that bill after purchase.


I break a pre-buy into five steps: 1) quick visual inspect; 2) records review; 3) spot check records to aircraft; 4) detailed aircraft inspection; 5) flight check. Steps one through three require no extensive disassembly. For example, you can use the preflight guide in the Rotorcraft Flight Manual (RFM) to complete step one.

If the aircraft fails the pre-buy at any of the first three steps you can walk away with minimal cost. I’ve seen a pre-buy breeze through step one and two, only to be shut down halfway through step three when several engine log cards did not match the installed engine.

Steps four and five usually involve the most time and have the greatest potential risk: a fastener breaks during cowling removal, a check-valve sticks during a chip plug check, a hot start occurs during a ground run. Just about anything that you could encounter if you owned the aircraft can happen at this point.

Whenever possible have the seller disassemble the aircraft and provide a pilot to operate it. If that’s not possible, be sure your agreement with the seller covers these potential problems.   


Since each pre-buy and each helicopter is unique, I cannot cover every possible issue. But I can offer a few tips that will address important point.

  • Aircraft Conformity: Check for conformity issues per appropriate FAA and OEM data (e.g., Agusta Bell vs. Bell parts issues, Airbus Alouette restrictions).
  • Airworthiness Certificate: Should be current and of type required for your use (e.g., Standard vs. Restricted).
  • Registration: Should be current and the seller is listed as legal owner/agent; aircraft is free of liens; confirm all registration changes since manufacture.
  • Logbooks: Seller should have all books from original airworthiness certificate issue entry to current date.
  • Component Cards: Should be complete and organized; compare part numbers and serial numbers to manufacturer Airworthiness Limitations sections and current aircraft status sheet; confirm time remaining on components fits your plans and price of aircraft.
  • Airworthiness Directives: Should be current per FAA listings.
  • Major Repairs/Major Alterations: Should have a Form 337 completed and a copy on file with the FAA.
  • Manufacturer Bulletins: Verify as needed.**
  • Operational History: Confirm physical locations and types of operations (e.g., GOM air taxi, logging, EMS, tours, public use, foreign-based) and modify pre-buy inspection criteria based on this history; if helicopter is in storage, verify preservation schedule and status.
  • Inspection Program: Should be current and of type available for your use. If not, review requirements to change program (e.g., AAIP to OEM program.); review status of corrosion prevention program.
  • Physical Condition: Verify that wear and tear matches operational history; pay attention to any  corrosion.
  • Flight Check: Verify that engine(s) meets power check limits per RFM; check that all system indications are within RFM limits. Is any flight control feedback and vibration levels acceptable?

* * Several notes on manufacturer bulletins: (1) They are not required for aircraft operated under Part 91. However, if you plan to select an OEM inspection program per 91.409(f), there may be an inspection-only requirement per a bulletin that has been previously incorporated into the OEM program. (2) There may be warranty credit still available on a bulletin with which you wish to comply. (3) If the aircraft is to operate under Part 135, verify status of bulletins for possible compliance requirement under the selected Part 135 maintenance program.  


After reading this article you probably decided never to buy a helicopter. But it’s not all doom and gloom. Having been asked to intervene and work out solutions on a few pre-buys that went south, I found it all boils down to the details.

A lack of a written guide and multiple misunderstandings between parties were the main culprits. Another roadblock was hiring BFE Bubba—whose last helicopter experience was changing Huey blades at “The Golf Course” in Vietnam— to look over a tricked out 206L-4. Believe me, not all Bells are the same.

Today’s aircraft buyers and sellers each have their own definition of what constitutes a pre-buy inspection. By simply following a dedicated checklist, using qualified personnel, and having all parties on the same page... life can be good… as you pull pitch in that new helicopter.

About the author: After 32 years maintaining helicopters in various capacities, Scott concluded a full time career with a major operator in 2014. When not pursuing future writing projects, he can still be seen around the flight line providing maintenance oversight, litigation support, and technical research services. He can be contacted at tekaviationllc@gmail.com.

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