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ROTORwrench…Tips, Tricks, Info… and a Laugh - June 2019

Posted 4 years 343 days ago ago by Scott Skola

Helicopter Maintenance Blog* 
June 2019

Looks like a new helicopter manufacturer is coming to town. There had been talk of a company taking over the old/new Bell building located at the Lafayette, LA airport. For those who remember, Bell was slated to build the 505 at this location, but back out for various reasons.

Media reports state the Swiss-based company, Kopter Group AG, will start hiring next year, with production to start on their model SH09 to begin in 2021. With the current downturn in the GOM, it may be a ray of hope for those looking for a change.

I saw an SH09 prototype at Heli-Expo several years back when it was marketed under the Marenco banner. Definitely has a lot of glass up front from the windows to the instrument panel. What’s even more interesting it’s sporting a HTS900 engine, grandson of the “legendary” LTS101. Wish them luck.

June is also the month I hightail it out of here for the Land of the Midnight Sun. So wait on any emails till I get back in August. Or, send them anyway and I’ll get to them when I return. Have a great summer!

In the history corner: 




ATA 05 
Maintenance Checks

Here’s a couple tips on the rotor-brake installation. One trick to save time on a 407 engine change is to leave the rotor-brake calipers, brake disc, and K-Flex input shaft installed during engine removal and installation. 

It will take a little more finesse and caution to accomplish the engine change, but it can save up to several hours overall. The main caution is to monitor the K-Flex as it slides through the forward firewall opening. To aid in that firewall transition, cover the K-Flex shaft tube with heavy cardboard or fabricate a set of protective shields from PVC tubing by splitting an appropriated sized PVC tube and securing with Ty-wraps or Velcro straps.

With the other engine items disconnected or removed, disconnect the K-Flex forward mount flange at the transmission. Compress the shaft forward flex coupling with the proper tool. Next disconnect the engine fuel nozzle supply line and remove the fuel nozzle. Removing the nozzle gives additional room to shift the engine aft as it is removed.

Now, with engine completely disconnected and supported by a hoist, start repositioning the engine assembly aft while lifting up on the burner can. The intent is to slowly move the engine aft to allow the forward end of the K-Flex to clear the forward firewall by positioning the engine burner can above the aft engine firewall. 

Once the K-Flex clears the firewall, most times you can turn the hanging engine assembly to the left side and out of the aircraft.

It may seem like a lot of effort to go through, but with some practice it will become second nature. Not to mention, working on the rotor-brake and K-flex on the ground is a lot better than needing two left hands and a 3rd eye to remove/install those items with the engine installed.

Now for those times when you do need to work on a 407 rotor-brake with the engine installed, get yourself a couple of ratcheting T-wrenches like those in Figure 1. You’ll need a 7/16” wrench and a 5/16” wrench.  These wrenches really make life easier and can be used on a 206 to boot.

Two more rotor-brake tips. When installing the brake calipers with the engine installed, pre-start the caliper mount bolt safety wire in the housing holes. It definitely beats trying to thread that needle through a mirror reflection, especially when you get to my age.

And finally, each rotor-brake caliper usually requires some shim to center the caliper on the disc. Once you calculate the shim glue it to the caliper before final assembly. If you don’t want to use any other tip this month, use this one. Trust me.

Need to catch up on the FAA InFOs. Here’s two: Helicopter Crew Doors and Pax Restraints with Doors Off.



Have an old tip or trick you’d like to share with your fellow mechanics? Or maybe a question that you can’t seem to find an answer to? Or just some info to pass on?  Send an email to: [email protected]

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 tinkering on aircraft for beer money. 

*To keep the hounds at bay, the information contained in this blog is for discussion purposes only.