HINTS AND TIPS

The Buttons below will take you through the different hints and tips that I feel will make your helicopter safer and more reliable.

Tail Rotor Blades

I was instructing in an older Exec 90 at the Torrance, CA airport several years ago. This particular Rotorway Exec 90 had been purchased by my student and he was the third owner. The area around the airport was typical of southern California in that it was totally congested so we flew West following the main street to the ocean. Once we reached the coast we turned south and did our flight training over less congested areas to the south.

The second day after a thorough pre-flight inspection we again headed for the coastline and then turned south at about 1000 feet AGL. About a mile south we I noticed the off shore fog bank was only a few miles out to sea and I was concerned that we might get stuck down south and not be able to return back the way we had come so I decided to turn around and head back to the airport.

Below is a photo taken during that flight. It was VFR along the coast but the fog bank is visible a few miles off shore.We are within auto distance to the left and were following the shoreline so that we could reach it if need be in an emergency

 

On our return to the airport we entered the traffic pattern and were planning on practicing some approaches. On the first approach and at about 20 feet AGL we suddenly felt a high pitched vibration .I immediately announced "I've got it" and took the controls to set the helicopter down. Just after set down the tail rotor shaft broke as you can see in the following photos. Had this happened elsewhere, it could have cost us our lives.

Note the rust on the tail rotor shaft. This ship was in a salt air environment and should have had a protective coating of at least grease to prevent it from surface rusting.

 

In the above photo you can see where the tail rotor shaft fractured. We later discovered that the factory had sold the previous owner a new set of tail rotor blades a few months before he sold his helicopter. I contacted him and he told me that during a practice autorotation he had hit the tail rotor on the runway surface damaging the outer couple of inches of each blade. He purchased and installed a new set before he sold the helicopter to my student. There was no notation of this repair in the airframe log book.

The tail rotor strike had concentrated the resultant forces onto the hole in the tail rotor drive shaft where the pulley bolt secures the pulley to the shaft and this is where it broke. If you suspect that the previous owner or you yourself has had a tail rotor strike, install new blades, pitch pins, bearings, pulley, and tail rotor shaft. We did this while I was there with Rotorway overnight shipping the parts to us. We then completed a week of uneventful flying and had a great time doing it.

The photo below is of a new set of Rotorway tail Rotor blades

Below is a set of tail rotor blades that contacted some tall grass upon landing.

This is precisely why I instruct my students to inspect the tail rotor blade end caps prior to every flight and it is included on the pre-boarding check list that we rigorously follow.

 

Don Eikel and Jim Dorman, two of my former students were flying Don's ship when they noticed a sudden high pitched vibration. I teach all of my students "if in doubt, auto out" . They immediately entered an autorotation to the ground, slid the helicopter on (Don had installed longer skids), and then looked for the cause of the vibration. The photo above shows that the spar of the tail rotor blade fatigued at the end of the pitch pin.

The FAA inspector said that the vibration was caused by the cracked spar allowing movement in the blade and that the break showed that the crack had been there for some time. Don had had experienced an incident early on with this ship prior to my giving him any flight training. I don't know if the tail rotor blades and all parts back there had been replaced after the incident.

The original tail rotor blades may have not been properly installed by the builder. Some unusual force obviously was applied to this area to cause this failure.

If they had not immediately entered an autorotation, the tail rotor blade would have departed and the results would have been much worse.

 
This area is up inside of the tail rotor blade and would be very hard to find during the pre-flight inspection. I will now pay more attention to this area on my pre-boarding check to see if there is any weakness in the tail rotor spar that is evident. If you have had a tail rotor strike of any kind, replace everything back there including your belts.
 
 

Be safe.

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The material on each page is the opinion of the author only and any actions taken by the reader relating to information on this site is the responsibility of the builder.