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 had gotten off pretty light ... John, the IA, didn't find all that much wrong with the airplane. 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 *%$#@! 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 John 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 John determined the W&B change would be negligible.
"But be sure to update the equipment list," John admonished me
"What equipment list?" I replied, instantly sensing from John'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, and that list must be revised whenever equipment is added or removed," John said, giving me his best do-I-have-to-explain-everything scowl.
I trotted over to the hangar to retrieve the POH from the airplane and brought it back to John's office. I flipped to the back of the W&B chapter, and sure enough, there was an equipment list. I showed it to John, but he shook his head.
"No, that's a comprehensive equipment list -- a list of everything that Cessna might have installed in a 1979 T310R," he 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 rummaged through my W&B documentation and finally came up with what we were looking for: a yellowed and somewhat dog-eared computer printout of the equipment installed in my particular aircraft when it left the 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.
"That list has to be kept updated to reflect what's actually installed in the aircraft," John said, shaking his head. "How on earth did we miss that all these years?"
The FAA publication that discusses all this best is FAA-H-8083-1, "Aircraft Weight and Balance Handbook," published in 1999. Quoting from that document:
"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."
Obviously, I'd been in technical violation for the entire 13 years I've owned this airplane.
"Well, what do I do now?" I asked John. "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 John, "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. 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. (You can download my spreadsheet to see how I did it. Note that on Feb. 19, 2007, a revised spreadsheet was linked here; if you downloaded the spreadsheet before Feb. 19, it has errors.)
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 13 years ago to be replaced with a King KT-76A, the old transponder was backed out of the W&B, but the transponder mount (0.6 lbs.) was forgotten.
The bottom line is that when the dust settled, the airplane's actual empty weight was lower than I thought.
After double-checking everything carefully to make sure I'd made no errors, I presented my handiwork to John, 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 13 years 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.
Next time you're preflighting 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.
See you next month.
Want to read more from Mike Busch? Check out the rest of his Savvy Aviator columns.