[Orv Neisingh]

Quite a few years ago I was hired to instruct Bob K. in his newly built 162f. Bob told me that the helicopter needed to have the main rotors balanced and I had just purchased my new Pro-drive balancer and I was eager to try it out. John Spurling, who produced the balancer, this was befor Microvibe offered one to us, told me that if I had any questions, just give him a call. 

I arrived at Bob's hangar and did a complete inspection of the helicopter, his workmanship was impeccable. After attaching the balancer sensors I fired up the engine and, sure enough, the main rotor system was really rocking the helicopter at idle RPM. I asked Bob if he had done a static balance and static lead/lag initial set up and he assured me that he had done them. As I increased the RPM, the helicopter began to shake even more dramatically to the point that I was afraid to take it to 100% RPM. 

I called John Spruling and asked him if I could take readings with the helicopter still sitting on the ground and informed him about the very pronounced shaking. He told me to just bring it to 100% and lift off to get the first reading no matter how bad it was shaking. Well, John was the expert so I gritted my teeth, ran the helicopter up to 100% RPM, or at least it sounded like 100% because the helicopter was shaking so badly that I could no longer see the rotor tach. I pulled the helicopter into a hover and all I had to do was to use my index finger to push the button that I had velcroed to the cycle to get that reading except I had such a death grip on that gyrating cyclic control that I could not even loosen the grip of one finger to push the button. 

At this point I thought that I was going to crash the helicopter but was finally able to get it back onto the asphalt pad safely. I still had no reading. I decided that once was enough of that kind of dangerous ride so I pulled out my rigging equipment and found that from the factory, the main blade rotor hub was off center by .007". That does not sound like much but the specs call for the hub to be centered on the main shaft to within .001". I reshimmed the rotor hub to spec and fired up the engine. This time the rotor system just purred smoothly and the reading in hover was around .2 IPS. 

After Bob's hover training he wanted to land at his business location down town Oroville. He owned a large dental practice in town with a huge lot and acres of open space behind his building. He had secured the permission of the city to be able to fly in and out of his business property so we departed the airport and flew to his business. 

We made a high recon and determined that there were no obstacles in our flight path. There was a McDonalds next door several hundred feet away from our intended landing spot and no pedestrians on his private property to be concerned with. We made our approach and landing, rolled the throttle down to idle and just then we were startled by two young boys on their stingray bikes just outside of the helicopter doorways. "Hey Mister, can we have a ride?". I grabbed the shirt of the boy closest to me and Bob grabbed the other one to keep them close to the helicopter as the rotor blades spun overhead. 

The boys had been over at the McDonalds, saw us make our approach and headed our way. One of them rode his bike just behind the spinning tail rotor to come around to my side of the helicopter. Fortunately no one was hurt by I certainly learned a valuable lesson: helicopters are kid magnets and that I needed to be very vigilant to insure that no matter where I landed, no one was nearby. 

Most cities now have ordinances that require public safety like the police or fire departments to be present for crowd control before a helicopter is allowed to land within their jurisdiction. In later years when I flew Medevac helicopters we would not land in a populated area without coordinating with the fire department or public safety at the scene to keep everyone safe.