Purchasing a Kit-Built Helicopter

As I travel around the country providing helicopter flight instruction, airworthiness inspections, and maintenance training to builders and new owners of different models of helicopters, I see an increasing trend in purchases of previously-built kits that have changed ownership once, if not several times. Often there are no maintenance or service records accompanying the helicopter, and sometimes the records that do come with it are inaccurate at best. The owner/repairman has the liberty to put anything on those records that he sees fit without anyone looking over those records to insure accuracy of the entries. I have found on more than one occasion that the records in no way match the actual service and maintenance history of the helicopter but seem to be concocted to provide a spotless history to aid in the sale of the helicopter. The buyer needs to spend some time investigating the actual history of the helicopter prior to laying down his/her hard-earned cash and finalizing the deal. I have learned this the hard way.

In this article I will provide several true stories that I am familiar with from personal experience. There are many more that are less dramatic that I could share but these that I am including should cause the reader to ask themselves whether or not they have taken the time to properly investigate the helicopter’s history prior to committing to it’s purchase.

Over the past 20 years I have built three helicopters, 2 Rotorways, an UltraSport 496 2 place and assisted in the completion and overhaul of many others. The first kit helicopter that I purchased was a previously built Rotorway Exec 152. I fell in love with this helicopter at first glance, purchased it and hauled it home. It was the most beautiful flying machine that I had ever seen (I had succumbed to a major case of got-to-have-it-itis). I knew nothing about helicopters so when I performed the pre-purchase inspection I went through the motions of checking everything out, although I did not have a clue as to what most of the components were and less of a clue about how to determine each components airworthy condition. It looked good to me so I wrote the check and proudly transported it to it’s new home while entertaining visions of soon soaring around the neighborhood in my new flying machine.

When the helicopter was unloaded from the trailer and snug in it’s new hangar I took the time to take an in-depth look at my new dream machine. I was surprised to see that the frame (which was at that time painted black) had several cracks at or near the welds where the tubular frame members were joined. Due to the black paint, the cracks were very hard to see unless the light was just right. This is why we always suggest the frames are painted white so that any cracks will show up as dark lines against a white background. These early kits were sent out with the frames just tack welded together and it was up to the builder to finish the welding process.

I called the factory to find out what to do about the cracks and Tom Smith advised me that the frame was most likely welded with an electric welder instead of with a gas torch. He explained that the gas torch heated the frame components evenly and as they cooled slowly the stresses were relieved evenly. If the frame was welded with an electric arc, the heating was less even and often the resultant stresses in the frame would, in time, lead to cracks forming in the frame.

I elected to take the helicopter apart down to the frame and then sand blast the frame to remove all of the paint and primer. Next I gas welded the entire frame where it was cracked. I used the torch to heat all of the remaining welds to anneal them, relieving any remaining stresses.

In those days we did not have the internet and the extensive networking of builders and flyers of Rotorway helicopters that we have now. It was up to each builder to figure out most of the building process on their own. The manuals provided by the factory were poor at best and contained many of the errors that we still find in the present 162F manual. Today any builder who wishes can take advantage of the great store of experience and knowledge that is out there with a click of the mouse, a few minutes on the phone, or a visit from one of the industries professionals to check out his/her progress.

I am often called on to assess the condition of a helicopter prior to it’s purchase and more often called upon to inspect and help repair one after the new owner has it home. As I am writing this article, I am on an airliner over Oklahoma returning to California to finish rebuilding a recently purchased kit helicopter that had a dubious past and nearly got my student and I killed 3 weeks ago. We had to wait for a few parts from the factory before we could complete the rebuild.(I share this so that others will learn by reading what I learned the hard way).

The new owner called me to tell me he had purchased an Exec 90 with all original components and 269 hours logged. The maintenance records were all there and “appeared to be complete”. After looking at all of the available information I gave the new builder a shopping list of parts to order so that we could replace those that had exceeded their calendar lives or had known problems. At the scheduled time I arrived in California to assist the new owner in replacing the secondary drive, all belts and hoses, installing new elastomeric main rotor bearings, new coolant, etc. During the airworthiness inspection I noticed that the upper engine mount was broken in 2 places and the engine adjustment screw was fractured, and several of the heat shields were cracked at their mounting brackets.

Once all of the apparent deficiencies were fixed and maintenance items were completed, we rolled the helicopter out to the ramp and fired the engine. It ran smoothly as we began the belt break-in procedure. After the belts were adjusted several times, and the blades were tracked and balanced we began hover testing the helicopter. We logged 4 hours of hover testing/inspection/belt adjustments and everything was running like a top. It was time to take it around the pattern for in-flight testing so hour five was spent completing several flights in the pattern with shut-down and inspection between each flight.

Hour six was the doosy! I had meticulously inspected every component of the helicopter that I knew to inspect and my confidence in the ship was growing with each flight. The belts had stretched to the point that we could fly an hour between adjustments. The southern California airport that we were flying from was totally surrounded by commercial and residential structures with very few emergency landing sites. I elected to head for the Pacific Ocean coast some 3 miles to the west were we would not be flying over the congested areas longer than we absolutely had to. This area offered us many emergency landing spots where beaches and bluffs overlooking the Pacific were plentiful.

We flew over the coastline for about 15 minutes when I decided to return to the airport to once again check the helicopter systems and belt tensions. We entered the traffic pattern as directed by the control tower, Turned down-wind over homes and factories, and while on our final approach to taxiway Alpha at about 30 feet agl, the entire helicopter began to buzz. I had never felt this in any of the hundreds of helicopters that I have flown and instructed in. I could feel the cyclic, collective, antitorque pedals, and even my seat vibrating at a high frequency that felt like the entire helicopter had been set to receive incoming cell phone calls and the switch was set on “vibrate”.

I have always taught my students, “When in doubt, auto out”. Since we were at approximately 30 feet in the air I just lowered the collective, headed for the ground, flared, and set the helicopter down. I told my student (he was already a commercially rated helicopter pilot and I was providingh him transition training) that I was going to exit the ship to look for the source of the BUZZ while he held the controls. I immediately heard a ticking sound coming from the area of the tail rotor as the ship idled. As I looked back at the tail rotor it suddenly stopped and fell downward at around a 30 degree angle. My heart nearly stopped as abruptly as the tail rotor had.

We shut the helicopter down and upon inspection found that the tail rotor shaft had fractured and broken where the drive pulley is bolted through it. I had never heard of this shaft failing before this event. We realized that had we been at altitude when the buzz first occurred, I would not be sitting here writing this article. The tail rotor would have departed the helicopter and the resultant lack of weight at the rear of the tail boom would most likely have put us into such a forward CG(center of gravity) that aft cyclic would not be able to keep us from becoming a lawn dart. It caused me to shudder to think of how close my student and I had come to becoming only memories.

What had I missed? I am considered to be one those who are knowledgeable when it comes to the Rotorway line of helicopters. I fly them, I build them, I inspect them, I instruct in them, I fix them, what had I missed that had caused this near disaster?

A call to the previous owner revealed that the reason that he had sold the helicopter was that he had suffered a tail rotor strike during a practice autorotation. He had decided that he would sell the helicopter after replacing the tail rotor blades that had been destroyed. If I had known about the tail rotor strike I would have given the tail rotor shaft a much closer look for damage, although the fracture was hidden under the drive pulley flange and would not have been visible without removing the pulley. Since there is no known history of this shaft breaking, I would most likely not have thought to replace the shaft even if I had known of the strike. In the future I will be keenly aware of this area and will replace that shaft if there is any suspicion of damage to the tail rotor blades.

I called the factory and talked to Tom Smith regarding the failure. He told me that the helicopter serial number had quite a history of replaced parts and that it had suffered several tail rotor strikes without any record of the tail rotor shaft being replaced. The factory keeps track of parts that are purchased for each serial number kit and that information could mean the difference between life and death for the new owner and his or her flight instructor.

Over the past 20 years I have learned an incredible amount about kit helicopters, much of it from personal experience. I make it a priority in life to pass this information on to other owners and builders, many of whom are my students, in order to keep others from experiencing the same problems and failures that I have encountered. I encourage everyone involved in this industry to share their experiences so that we can all live to enjoy these marvelous flying machines while respecting their limitations.

Part 2.

Several years back I was relaxing at home after returning from a 10 day instructional trip. That afternoon I received a call from a new owner of an Rotorway Exec 90 who needed flight training. He was only a 2 hour drive from my home and wanted to know if I could start his training the following morning. I agreed since I was not scheduled for anything for the following week.

When I arrived at his hangar I performed an extensive airworthiness inspection and we spent nearly 6 hours fixing and adjusting a number or components that needed attention. I inspected the log books that came with the helicopter and saw that over the 296 hours that the helicopter had flown, the required maintenance had been performed exactly as called for in the helicopter’s maintenance manual. I was actually impressed by the thoroughness with which the previous owner had logged everything that was done to the helicopte,r including every valve adjustment and bolt torque performed over it’s life. It had been given an annual inspection just prior to my student purchasing it so everything appeared to be good to go.

After determining that the helicopter was ready for flight, we fired up the engine and began our hover testing. The engine was a bit weak but that is not abnormal for one having nearly 300 hours on the meter. It seemed to run well so after several short hover flights I determined that it was safe to begin my student’s hover training. About 30 minutes into the hover training the engine made a loud bang and then quit. I set it on the ground, and we hiked back to the hangar at the other end of the airport to get my student’s truck, a tow rope, and the helicopters ground handling wheels.

We put the wheels on the helicopter, attached the rope to the bumper of the pickup and the front landing gear legs of the helicopter. I agreed to walk along holding the tail boom of the helicopter down to lift the front of the skids as he would SLOWLY drive the truck to pull the helicopter back to the hangar. All was going well until about half way down the runway he received a cell phone call and forgot that he was pulling the helicopter behind him. The truck started going faster and faster and my walk became a trot and then finally long striding jumps as I attempted to keep the helicopter tracking behind the now accelerating truck and my oblivious student. Just as I was about to loose control of the helicopter (I could envision myself sprawled on the runway as the helicopter careened off into the ditch that ran along it’s length) my student glanced back and slowed down.

We finally got the helicopter back to the hangar and removed the valve covers to inspect the valves. We found one of the exhaust valves had stuck in the open position and a piston had hammered into it causing the top of the piston to disintegrate. We decided to remove the engine and send it back to the factory for overhaul. They determined that the valves had not been adjusted in over 100 hours and this lack of maintenance had led to the valve failure. Remember that the maintenance manuals were complete and showed that all valves had been adjusted as per the manual.

The new owner called the builder who had made the log book entries and who had given the helicopter a fresh annual inspection including logging the recent valve adjustments. The previous owner told the new owner that the ship was impeccably maintained and that it was not his problem, and don’t call him anymore as he was not interested in hearing about any problems with the helicopter. Obviously this previous owner had doctored the maintenance records to show complete compliance with the helicopter maintenance schedule while neglecting to actually perform the maintenance itself. We need to be very careful in looking at the history of any helicopter that we purchase. The paperwork will only show what the previous owners wish them to show. If that person does not possess the degree of integrity that we assume he should have, the logs may show a much brighter picture of the machine than what we are actually getting when we hand over the purchase money.

If you are considering the purchase of a used kit helicopter, do some investigation into it’s history. Inspect it thoroughly, and ask the seller the reason that components have been recently replaced. These machines can be a lot of fun but can also bite hard if something goes wrong at the wrong time.