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Race Engine Technology Magazine

This page contains a list of the failures of RotorWay secondary shaft systems which we could obtain from public sources. A few of them are documented in the NTSB database, but reports of older failure-accidents are mysteriously disappearing from NTSB listings. Some of these data came (a) from the ROG website (our thanks to Ron Curry), (b) from talking to the involved owners, and (c) from talking to people whom we believe to know, with reasonable reliability, about specific cases.

It is certainly not our intention to embarrass RotorWay. These data are presented only to document the severity of the problem.

For the purposes of this synopsis, the only data items of interest to EPI are the aircraft type (162, 90, etc), the configuration of the secondary (30mm-three-bearing, 30mm-two-bearing, 30mm-spherical-bearing, and 35mm-spherical bearing) and the main rotor drive system (the factory chain drive or the Pro-drive™ toothed-belt).

The incidents listed here are arranged in reverse-chronological order. The blocks containing "?" represent data which are currently unknown to EPI.

Of the 17 listed failures, 5 are documented to have been on chain drive systems, 8 on belt-drive systems, and four are unknowns. The only three known failures of the 35mm shaft have been on ProDrive installations. The page Summary of Secondary Shaft Loads explains why.

The one publicly-known chain drive-35mm-shaft failure was on a factory ship in February of 2003, but that shaft broke down in the 1" diameter portion below the 8-sheave V-belt pulley, and was probably caused by at least two prior tail-rotor strike / destruction incidents.

In order to make this small database more meaningful, we NEED to fill in data where there are currently "?" symbols. The reason we need the information is to develop a better idea about which, if any, systems are the most failure-prone, and to seek a better explanation for those probabilities.

We strongly encourage anyone with specific information about any of these unknown data items or about any failure not listed here to provide us with those details. We promise that your anonymity will be protected if you want it to be.

We know that there have been failures in addition to those shown here. Those data are not yet listed because we have not been able to confirm the details of those incidents.

Knowing the workings of the Experimental World, we would bet that there have been several additional failures which have gone unreported. Some of those might have resulted in a successful autorotation and produced no damage to the ship or to any persons, in which case a report is not required. Others may have occurred in a sufficiently private context that no additional "help" from the Feds was deemed necessary.

We think that RotorWay themselves are in the best position to know about the true failure rate. After all, they have had at least two (known) failures. AND, who do people call to order replacements for their broken hardware??

Again, EPI welcomes and encourages any additions to this list or clarifications / corrections to the existing data. We assure anyone who wishes to contribute information that it will remain completely confidential. Only those data items shown in the list above will be published.