My 1979 Cessna T310R

My 1979 Cessna T310R

A funny thing happened as I was finishing up the annual inspection on my 1979 Cessna T310R back in March of 2000. The inspection was complete, and I gotten off pretty light. My IA didn’t find all that much wrong with the airplane. (This was years before I became an IA myself.) What discrepancies had been found were now all resolved. The airplane was finally back together and all closed up. The AD research was done. All that was left was the paperwork.

One of the few discrepancies had been an ELT that flunked its annual FAR 91.207(d) test—the [email protected]#$%* thing wouldn’t go off no matter how hard I whacked it—so I had yanked it out and installed a shiny new TSO-C91A unit, complete with a panel-mounted switch/annunciator module. I asked my IA whether or not a weight-and-balance revision would be necessary. It turned out that the new ELT weighed almost precisely the same as the old one, and the panel module weighed next to nothing, so the IA determined the W&B change would be negligible.

“But be sure to update the equipment list,” the IA admonished me

“What equipment list?” I replied innocently. I instantly sensed from the IA’s expression that this was not the answer he wanted to hear.

“Your POH or W&B Report is required to include an up-to-date equipment list, said the IA, giving me his best do-I-have-to-explain-everything scowl. “That list must be revised whenever equipment is added or removed,” he added.

Where’s that list, anyway?

I retrieved the POH from the airplane and flipped to the back of the W&B chapter. Sure enough, there was an equipment list. I showed it to my IA. He shook his head.

“No, that’s a comprehensive equipment list—a list of everything that Cessna might possibly have installed in a 1979 T310R,” the IA explained patiently. “It could serve as an aircraft-specific equipment list if those items that are actually installed in your aircraft were checked off in the comprehensive list. But they’re not.”

Sure enough, the equipment list in the POH had a column titled “Mark If Installed,” but that column was completely blank. There was no indication of what equipment was actually installed in my airplane.

I returned to the airplane and rummaged through my W&B documentation, finally coming up with what I was looking for. It was a yellowed and somewhat dog-eared computer printout on sprocket-fed fan-fold paper—the kind that was used back in 1979—that listed the equipment installed in my particular aircraft when it left the Cessna factory, complete with the weight and arm of each item. The only problem was that this printout hadn’t been revised since the day Cessna generated it in 1979, despite the fact that by now almost all the original factory-installed avionics had been replaced with newer stuff. Sigh.

“That list has to be kept updated to reflect what’s actually installed in the aircraft,” my IA told me said, shaking his head. “How on earth did you go all these years without someone catching this?”

A little research convinced me that the IA was correct. The best reference is the FAA’s “Aircraft Weight and Balance Handbook” (FAA-H-8083-1B) published in 2016. Quoting from this handbook:

An equipment list is furnished with the aircraft which specifies all the required equipment, and all equipment approved for installation in the aircraft. The weight and arm of each item is included on the list, and all equipment installed when the aircraft left the factory is checked.

When an Aircraft Maintenance Technician adds or removes any item on the equipment list, he or she must change the weight and balance record to indicate the new empty weight and empty-weight CG, and the equipment list is revised to show which equipment is actually installed.

Bringing it up-to-date

“Well, what do I do now,” I asked my IA. “Do you want me to mark up Cessna’s printout, crossing off the equipment that has been removed, and adding in the new equipment by hand?”

“You could do that,” said the IA, “but it might be nicer simply to make up a new equipment list on your PC and printing out a clean, up-to-date list.”

That idea appealed to me. It would be straightforward to enter all the equipment into an Excel spreadsheet. In fact, it quickly occurred to me that if the spreadsheet included weight and arm for each item (as Cessna’s original did), it would be easy to have the spreadsheet calculate the aircraft empty weight and CG. Then, when equipment was added or removed in the future, simply entering that information into the equipment list spreadsheet would automatically produce an updated W&B. The more I thought about it, the more I became convinced this was the way to go.

That evening, I sat down at my computer and proceeded to enter all the equipment from the Cessna printout into a spreadsheet. There were about 125 items to enter, and it took me about an hour. My spreadsheet was structured in two sections, just like the Cessna printout: Section A contained “required equipment” and Section B contained “standard and optional equipment.”

Then, I went through each W&B amendment in sequence, removing and adding spreadsheet lines to correspond with the equipment that had been removed from and added to the aircraft over the years. To provide traceability, I did not delete any items from the spreadsheet, but simply set the “quantity” field of each item of removed equipment to zero and then added a new line for the new equipment that replaced it. All revised lines were identified with “DELETED <date>” or “ADDED <date>” entries in the remarks column

Finally, I added a third section to the spreadsheet—Section C—in which I entered the necessary formulas to add up the weights and moments for each item in Section B, add it to the standard empty aircraft weight (the weight of a fictitious aircraft with only required equipment), and calculate the actual empty weight and CG of my aircraft.

The whole project took about two hours, and the result was a very nice-looking and up-to-date equipment list.

A few (pleasant) surprises

In the course of making up this spreadsheet, I discovered a few interesting things. The first was that a few of the items of equipment that Cessna listed on its computer printout had never (so far as I could tell) actually been installed in the aircraft. One such item was “Handset & Boom Mic., Combination” (0.4 lbs.), and another was “Approach Plate Holders” (0.2 lbs.). No big deal.

Of somewhat greater significance, I found that certain items on the original Cessna equipment list had been removed from the aircraft, but apparently the removals were never recorded in W&B amendments. For example, when the original Cessna 400 transponder was removed almost immediately after I bought the aircraft and was replaced with a King KT-76A; the old transponder was backed out of the W&B, but its mounting tray (0.6 lbs.) was forgotten. The bottom line is that when the dust settled, I’d picked up a few extra pounds of empty weight for my trouble.

Legal again

After double-checking everything carefully to make sure I’d made no errors, I presented my handiwork to the IA, who triple-checked it and then affixed his signature and A&P/IA certificate number, thereby making it an official part of my Airplane Flight Manual and Weight & Balance Report in the eyes of the FAA.

I’m glad I went through this exercise, although I’m embarrassed that it took me more than a decade to discover that “my papers were not in order.” Perhaps I was the only aircraft owner out there blissfully flying around without an up-to-date equipment list, but somehow I doubt it.

Since that time, I became an IA myself and have made quite a few equipment changes to the aircraft. Having the computerized equipment list and automatic W&B calculation has repaid that two-hour effort many times over.

Next time you’re pre-flighting your airplane, you might just want to grab your POH and W&B papers and eyeball the equipment list to make sure it has been kept up to date. If it hasn’t, you might just want to do something about it before the next annual…or ramp check.

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from Amazon.com in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from Amazon.com in paperback and Kindle versions. (508 pages).