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Instrument Failure – When the Dog Bites and the Bee Stings

A few of my least favorite things.

It’s sunny and 83 degrees with a light breeze in St. Thomas, U.S. Virgin Islands, as I write this; the only sign that Christmas is fast approaching are the multicolored lights strung in Windbird’s rigging and occasional faint notes of familiar holiday tunes drifting across the water. I wish I could report that Dawn and I have been sailing across the Caribbean Sea, running with our dog Piper over sugar-sand beaches or spearfishing and lobstering on remote reefs — but alas, I cannot. We are stuck on the dock, where I spent the past two weeks toiling away on projects in Windbird’s conspicuously empty engine room and dark hole of a bilge. Your envy over my tropical yuletide just instantly evaporated, didn’t it?

It’s a long and boaty story best told over a couple drams of rum, but the short version is that while Windbird was stored on land in Puerto Rico this past hurricane season, her cockpit developed a severe leak into the bilge that went unnoticed by our boatsitters for months, until the engine and transmission were submerged in accumulated rainwater. Engine seals are good at keeping oil in but lousy at keeping water out, and in tropical heat, internal moisture turns fine machinery into rusty scrap metal in short order. Faced with the prospect of ripping out the guts of the boat to overhaul a high-time engine, we elected to beat the 40 miles upwind to St. Thomas and replace our formerly trusty diesel with a brand new model. Go ahead, email me that joke about what “BOAT” stands for — it gets more hilarious every time.

A friend recently posited that I’m cursed when it comes to mechanical things. You might recall that my ownership of a 1953 Piper Pacer ended with the untimely death of its engine. A routine annual inspection in Vancouver, Washington, revealed that the Lycoming O-320 had just started making copious metal — including a good-sized chunk of main bearing — and was basically on the verge of catastrophic failure. The last flight before the annual I’d taken a good friend and his two young boys on a tour around Mount St. Helens and over some very rough terrain. Thinking about it still gives me the willies. The engine had only had about 1,000 hours on it since the last major and I treated it well during my ownership — but the overhaul had been almost 30 years before and the engine had sat basically idle for several yearslong periods. Any pilot with a lick of sense will tell you not to buy that airplane. I guess I was the kid who had to grab the hot stove to understand why Mom warned him not to.

So I think of the Pacer incident not as evidence of ill fortune, but rather as a natural consequence of failing to heed the wise and time-proven advice of more experienced aviators. The fact that I survived the lesson with life and limb intact suggests a certain reserve of luck, as do my only other two brushes with engine failure in more than 13,000 hours of flying.

The first happened while I was working on my CFI ticket at the tender age of 19. I was demonstrating ground reference maneuvers at 800 feet agl in a Piper Warrior when the engine developed a sudden and fairly vigorous vibration and lost partial power; unable to turn more than 2,000 rpm, I had just enough energy to make a small airstrip about 5 miles away. The cause turned out to be the combination of a failed magneto and one bad spark plug on the other mag. Voila, a three-cylinder O-320. I don’t recommend it.

A few years later, while freight-dogging in a Piper Lance, I was doing a rolling runup just before takeoff from my home base when the engine abruptly went berserk, firing at random intervals that averaged perhaps once every three or four revolutions.

There was just enough power to limp back to the ramp. Several mechanics jovially sauntered up with Cheshire Cat expressions, joking about what the idiot pilot did to their airplane this time. After a little investigation, the grins disappeared. Though the Lycoming IO-540 is about as bulletproof as aero engines get, a few models had a single point of failure in the ignition system. The Bendix D2000/3000 combined both magnetos into a single housing, with both mags driven by a single nylon-distributor gear. This had shattered into three pieces, with the remaining teeth firing the mags out of order in irregular fashion. Had the failure occurred one minute later, at low altitude over intensely congested SoCal sprawl, I might not be here to tell the tale.

Isolated incidents aside, over the years I’ve mostly been impressed at just how reliable airplanes are considering the age of the GA fleet, the sometimes-irregular maintenance and the harshness of the conditions under which they operate. Most of my “uncomfortable” moments over the years have come because of weather, my own stupidity, an errant student — or some combination thereof — but generally in perfectly good airplanes. Outside of the engine foibles already mentioned, only a few mechanical snafus stand out in my mind.

I had a small electrical fire in a Seneca whilst on downwind. We threw down the gear, shut off the battery master and landed. No big deal. On descent into Portland in a Q400, oily smoke started pouring into the cabin and cockpit. Some quick troubleshooting with the QRH eliminated the culprit, and the subsequent emergency landing was pro forma. A weird electrical glitch in an MD88 provided a distraction at the worst-possible moment that could have resulted in a bad situation. Most other failures were so benign that they were forgotten within a week or two. But there was one incident so improbable that I felt as if the airplane were a malevolent being plotting my destruction.

RELATED: Webinar Highlights Inflight Hazard Avoidance

In November 2001 I took a break from my senior year of college to jet out to Southern California for a long weekend of cross-country flying with my former instrument student, Ed Kraus. We rented a Piper Arrow from the school where I had instructed the previous summer; however, as our reserved Arrow II had recently been landed gear-up, we were instead issued a newer and prettier Arrow III. I wasn’t overly excited about the upgrade, for I’d flown this airplane before and dubbed her “Christine” after suffering a number of failures. On our second day of flying, Ed and I filed IFR up the coast to Eureka. Cruising up the central California coastline on Victor 27, I noticed that the turn coordinator had stopped working. The weather was pretty crummy in San Luis Obispo, so we decided to keep going to Monterey, which had a 1,000-foot overcast.

Shortly thereafter, nearing Big Sur VOR, it became apparent that the attitude indicator and directional gyro were at odds. Every time the AI showed us wings level, our heading drifted to the right; but when the DG indicated a steady heading, the AI showed a slowly increasing left bank. The compass broke the tie: our attitude indicator was definitely dying. Being vacuum-powered, it was completely independent of the electrical turn coordinator — but they failed within minutes of each other, while we were in solid IMC at 8,000 feet over rugged terrain.

We declared an emergency, turned southwest out over the ocean, and pulled the power to idle. Ed held wings level as best he could with the failing AI, until it rolled over altogether. Then I called out compass headings and suggested corrections; magnetic dip provided an early warning each time we wandered into a bank. The blind descent seemed to take forever before we finally broke out at 800 feet. There wasn’t much horizon, but winter swells on the North Pacific gave the surface enough definition to keep the greasy side down and scoot northeast to Monterrey.

After landing we composed ourselves, went to lunch and ate a tasteless meal in stone-cold silence.

Because our planes are normally reliable, because we so depend on them to keep us and our loved ones safe, and because we come to know them intimately and talk to them fondly and imbue them with personality, it’s pretty unsettling when they let us down in a big way. It feels almost like a personal betrayal of trust. But our beloved machines are of course merely interdependent collections of complex mechanical gadgets, each one of which will naturally wear and eventually fail if left unaddressed. Every failure is an example of cause and effect, and thus is an opportunity to learn.

The old saw has it that whatever doesn’t kill you makes you stronger; I counter that it makes you smarter, if you only pay attention. You might learn how to prevent a reoccurrence, or how to better recognize impending failure, or how better to cope with the loss of a critical system.

My simultaneous instrument failures taught me the value of multiple layers of redundancy and the importance of an immediate exit of IMC if even one layer fails, and also highlighted the value of small mobile AHRS units when that technology became available. When I interviewed to fly Lances for Ameriflight, I confirmed that they had replaced their single-drive magnetos with independent units. My experience owning the Pacer means that the next aircraft I buy will have had a major overhaul by a reputable shop within the past decade and a history of steady usage since. And as for Windbird, my preparations for the next hurricane season will be greatly informed by the frustrating and rather expensive lessons I’m learning as I spend Christmas toiling in her engine room. Of course, if you’re a smarter man than I, then you make it a point to learn your lessons from other people’s misfortunes. It’s a lot easier, safer, and cheaper than getting your education from the school of hard knocks.

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