Chapter 648

Longmont, Colorado

Welcome to Chapter 648

President's Corner

 
 Well, it is winter, and we seem to be in that pattern of having snow and cold on the weekends.  But that didn’t hinder us from having a well attended and great program February 10th.  The Rocky Mountain Ravens were going to do a program about the fundamentals of formation flying, but the weather didn’t allow that to happen, so Dr Al Carr spoke about the affects of high altitude flying and hypoxia. It was very informative and spurred good questions and conversation. It’s very important that we all know the signs and symptoms of hypoxia since we live at altitude and fly over the mountains. If you would like to experience this in a controlled environment, a traveling chamber will be coming thru Colorado in June. It will be at Centennial Airport, hosted by Wings Over The Rockies and the FAA, in conjunction with various Colorado pilot organizations and the FAASTeam,  Here is the link for more information.  

In March, The Rocky Mountain Ravens will return for a program. Everybody has seen flyovers, but the question is, what does it take to do that? The program will be an abbreviated ground school on formation flying and will answer that question.

The March 9th meeting will be at the same hangar as the February meeting was. Building 15, unit 44. Meet & greet with coffee & donuts at 9:45, promptly starting the program at 10:00, finishing off with conversation and light lunch.

A heads up for April. We will not be having our normal second Saturday of the month meeting.  Instead we will be meeting on Friday April 5th from 5:00-7:00PM at The St Vrain Innovation Center. The students there will show off the RV-12 they have been building, their drones, and the simulators they have been doing ground school training on. This will be an exciting evening that will lead nicely into our Young Eagles event in May. We plan on having pizza afterward. 

Happy flying,
 
Chad Rennicke
President, EAA Chapter 648 
Longmont Weather

Next Meeting

The March meeting will be on March 9th at 9:45am. The event will be held at Chad's hangar. The gate code is 1200.

 

EAA

 

 

 

 

Treasurer's Note 

For those who haven't, please CLICK HERE to renew your membership, or bring cash/check to the next meeting.

Dues are due this month!

Thank you!

Kyle Foley

Tech Counselor Article

"Raven Flight -Knock It Off-Lead Electrical Failure!"

By Dan Berry  Chapter 648 Technical Counselor

 

That was my radio call after completing a pass over the Longmont airport flying lead with our RV formation team, the Rocky Mountain Ravens with a four ship flight.

The team did their job, as briefed, getting in a loose route formation and asking what I needed.

Following rule 1, Fly The Airplane, and confirming again, my Amp Meter was ZERO and my Volt Meter was indicating 12.3V, I had a hard failure.

All I needed was an airport which I had underneath me about a ¼ mile to the south. It was a civilized training day with all the touch-and-go C172 Heavy students in the pattern.  A downwind instructor actually gave me permission to cut in front of them on a direct base to 11  and land. Headed towards the runway, all traffic clear and accounted for, I had the overwhelming urge to do some trouble shooting. However, that clearly violates Rule 1, Fly The Airplane. My WWII grandfather was my primary instructor. Rule 1 runs deep in my thoughts and actions.I had a runway below, clear traffic, a usable flying machine. I decided to stay the course, relax, fly a close pattern and land. Troubleshooting is much easier in front of the hangar.

Cycling the Alternator and Field breakers did nothing. All wires under the panel were secure and in good condition. Time to pull the cowl.

First clue I found was some discoloration inside the cowl near the alternator. Second clue was that the electrical terminal boot had black residue on it, so I thought.

Upon further investigation I realized it was a hole. It made no sense that the cowling rubbed a hole in the boot, I knew I had plenty of clearance with 675 hours and many conditional inspections with this configuration.

I pulled on the boot and it crumbled in my hand along with a nut attached to the burned off battery buss output post  threaded stud. The hole was from a burn through event.

It started making sense.

The B-Nut vibrated loose, opening a gap between the B-Nut Stud Nut and the Wire Terminal End. This allowed arching and sparking to occur, every spark burned metal from the stud until it broke off, a very effective arch welder/plasma cutter event. The boot contained the sparks until it burned through.

EAA

Upper Boot with Burn Through compared to the lower New Boot

 

EAA

Looking inside the burned metal inside the boot

 

EAA

The melted away Wire Terminal, Stud and Nut

 

What went wrong? I installed my BandC L40 alternator per the supplied instructions and included hardware. I called BandC, I am not the first person with this issue and it requires the alternator to be returned for factory repair. Time and money, 1 week, $150 later all was repaired.

The instructions for the L40 simply say “Install the large gage wire from the Battery Master Contactor on the copper post labeled “B”.  This is often referred to as the BNut. No torque values declared  and no lock washer supplied.

I prefer to use a torque value and did find 50 in-lb in other BandC documents.

Hartzell Alternator Models ES-6904 Owners Manual requires inspection for Arc Marks near the BNut/Output post AND requires a Split Lock washer in the hardware stack with a torque of 40-50 In-lbs.

My current installation now has a split washer, required torque AND I added a strip of Torque Stripe Seal to visually inspect any movement of the hardware stack all under a new electrical terminal boot.

Lastly an inspection line to my Annual Conditional Inspection and anytime I have my cowling off the airplane.

Avoid being a flying arc welder, keep your BNut tight.

Dan Berry

EAA Chapter 648 Technical Counselor

Lifetime Member 222073

 
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