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

Posted 5 years 73 days ago ago by Scott Skola

Helicopter Maintenance Blog* 
April 2019

This past month, the 2019 Heli-Expo came to Altanta, GA and left. Haven’t heard much about it as it appeared to be rather low-key event this year. But from what I did hear it seems there’s a definite shift to Black Hawks and Chinooks in the utility arena.

March was also the month the Sikorsky-Boeing SB-1 Defiant took its first flight. Congrats! For more:

And in another testing first, NASA released video of the January flight testing of the Mars Helicopter in March. It will be combined with a rover for the next Mars mission in 2020. Videos here:

In the history corner: 




ATA 05 
Maintenance Checks

While some think the Rolls Royce C-47 engine found in the 407 is a “new” engine, it’s not quite that new. It’s basically a C-30 with FADEC and magnetic speed pickups (due to the FADEC). With that little tidbit out the way, here are some engine inspection tips.

Depending on your maintenance program, the engine is usually inspected every 150 and 300 hours. And one of the requirements is to change the engine oil and oil filter. This can get quite messy, especially if performing it outside on the flightline and on a windy day.

Enter the Oil Drain Bucket Mark III. It’s really nothing fancy. Simply take your standard 5 gallon bucket (figure 1, light gray) and modify the bucket lid (dark gray) with some 1” PVC tubing and fittings. There can be any number of variations. 

Start by installing some sort of bulkhead fitting through a hole in the bucket lid. Next, measure from the fitting up to about 8” below the engine oil cooler and oil tank drain tubes that protrude from the aircraft lower aft fairing area. Cut and install a PVC tube (blue) into the bucket lid bulkhead fitting.

Now, install a PVC compression fitting (dark green) and tube (light green) similar to those installed on house sink drain lines. Depending on your geographical area you may need research PVC sizes to get the proper combination, but don’t go smaller than a 1” tube. Back at the aircraft, with the upper bucket tube (light green) slid down into the lower bucket tube (blue), verify it fits under the engine pan drain tube on the aircraft. Adjust the lower tube length as needed. 

Once complete, when draining the engine oil tank or cooler, position the Mark III bucket under the specific drain tube. Adjust the upper tube (light green) up until it surrounds the tube then open the engine oil tank or cooler drain valve. With no exposed area, the oil will only drain down the tube and into the bucket. Repeat at engine pan drain tub when necessary.

However, even with the Mark III bucket, you can still make a mess when replacing the engine oil filter. By placing a 1 gallon, or larger, plastic bag under and around the oil filter housing prior to the filter element replacement, you will capture most of the oil spillage as the housing is removed. It even provides a convenient place to drop the old filter element into.

With the residual oil and filter in the bag, you can now hold it up against a light for a quick review of condition. As an added step, you can line the engine pan with 1 or 2 oil absorbent pads to catch any errant drops or spills.

As a side note, even if some oil does make it down the engine pan drain and into the bucket, it’s always a good practice to chase that oil with a little solvent to flush out the drain line. Otherwise, you’ll be wiping up oil dribbles at the external pan drain tube fitting for the next few flights. Or worse, that new-hire pilot will keep writing up an oil leak at the drain tube.

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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.