September 2018 Safety Corner
This month, I decided that it would be beneficial for club members to hear from one of our members, Dan Wilkey, who recently experienced full electrical failure in the Bonanza and how he handled the situation. I appreciate Dan sharing his experience, what he learned, and what he’d do differently. Dan did a great job of calmly handling the emergency, but above all, FLYING THE PLANE AS HIS NUMBER ONE PRIORITY.
Here’s Dan’s account of the incident:
I had just taken off from Creston, IA, and the first indication of a problem was right after take-off, when the JPI started flashing 11.7 volts. However, the ammeter still showed the alternator was charging. At the time, it didn’t seem reasonable that both could be true, and I had no way of determining if the JPI was accurate. So, I cycled the alternator to see what would change, and the JPI shut off, then came back on when I turned the alternator back on. More on that later— I knew that shouldn’t happen, but with the
ammeter showing a charge, and everything else working fine, I continued on. When I cycled the alternator, I validated that the ammeter swung from Charge to Discharge, I began to think maybe the JPI was failing. However, over the next few minutes, the JPI showed the voltage was continuing to drop, and eventually the JPI started blinking out, before finally staying off. The 430 and transponder were still working fine, so I still didn’t know if the issue was isolated to the JPI. Shortly after that, I smelled something strange (not like a wire burning smell, but just something unusual), I asked ATC to divert to the closest airport, Atlantic, IA, which they cleared me to. Within less than a minute, the entire comm. stack went out, I shut off the battery and alternator switches. Fortunately, I still had Fore Flight for navigation, so I circled over Atlantic while I worked out power and slowed down. I cranked down the gear and began a circling decent through the IMC. Since my ADS-B receiver (FlightBox) is self powered, I was still able to get FIS-B weather in ForeFlight, which allowed me to confirm the ceiling height (3900′ AGL) and preferred runway at Atlantic. After exiting the IMC, I was
able to locate the airport quickly, and get in the downwind for runway 02. With no electrical, I couldn’t trigger the PAPI to turn on, as I executed a no-flaps landing. I crossed my fingers that the gear was fully down and locked (no indicator lights), and I quintuple-checked that I couldn’t get the crank to turn any further.
Once on the ground, I knew ATC would be looking for me, which was confirmed by the fire truck showing up at the airport. They had already contacted the FBO, asking if they had seen us. The first thing I did was let MSP Center know that everyone was safe. There happened to be an IA at Atlantic, and he looked everything over, but couldn’t find anything obvious. He hooked up his alternator tester and had me start the engine. When I did, the JPI came on and it was showing the normal 13.7v, and his tester showed the alternator was charging. With everything working as expected, I took it up in the pattern to see if the low voltage or smell returned. With very thing still working normally, I decided to make the short flight back to Millard. However, not knowing the exact cause of the loss of electrical, I definitely didn’t trust it to fly to my intended destination of Pierre, SD. Oracle checked the plane over, and they found that a bad key switch was allowing the starter to stay on. I shared all the details I could with Oracle’s IA, and it all does seem to add up: Having just landed in Creston to pick up family, I did not do another run-up (no mag check). Apparently, after starting the engine, the starter continued to run, which placed a sizable load on the electrical system. Not as much as it does when cranking the engine, but apparently enough that the alternator couldn’t keep up. Had I not had a headset on, I may have heard the starter howling. I immediately lined up for departure and took off, so as not to exceed the void time of my clearance.
With the alternator continuing to outpace the charging of the alternator, the battery voltage started to drop, as indicated by the JPI. However, since the alternator was still charging, the ammeter was also telling the truth. This is a function of where the ammeter is placed in the electrical circuit.
Without going into gory details on how an ammeter works, this would be one of the few situations where the gauges could show low voltage with the alternator charging normally. Anyway, when I cycled the alternator, the battery voltage must have dropped below the JPI’s lower limit, which is why it shut off. The rest of the avionics stack must not be quite so sensitive, which is why it stayed on. However, once the voltage got low enough, everything blanked out. We suspect the smell may have been from the
starter getting warm from running for 20 minutes. Oracle confirmed that the key switch was bad by starting it on the ground, pulling the mixture, and then watching the prop continue to spin since the starter never shut off. They were able to duplicate it several times, so the key switch was replaced. As you can imagine, I’ve ran the situation through my mind countless times, looking for areas where I could have done something different or better. Over the years, I’ve wrestled with the value/necessity of doing a run-up after a short layover between flights. I still can’t say whether I think a full run-up is “necessary”, but even an informal “mag check”
while taxing would have prevented this situation. I’m guessing this isn’t a common failure, but in hindsight, it would be easy to avoid. Also, the thought of the starter being stuck did occur to me inflight, but in the moment, I didn’t feel it would be prudent to start messing with the key switch while dealing with the other issues. Not that dropping a mag inflight would spell certain doom, but I’m naturally inclined to follow the saying of “If it ain’t broke, don’t fix it. When I got to Pierre the next day (after driving there), someone said: “I guess your flight didn’t go as planned”. Actually, it did……it just wasn’t a plan I thought I’d ever really need to execute. You see, I believe that luck favors the prepared. That’s a big reason that I bring my FlightBox on every cross country flight, or when flying in actual. I intentionally have it running on its own battery, in case of complete electrical failure, or even if just the alternator goes out. The less load on the main system, the better. Also, I’m very glad that I read the book “Stick and Rudder”. If nothing else, there is one key piece of information that I use anytime I’m landing at a field with no glide path guidance– the spot on the ground that isn’t moving up or down is exactly where you’re headed (the book describes it in detail). This may be inherent knowledge to some, but 99% of my landings have been at fields with a VASI or PAPI, and many are on all the time. With no radio, I couldn’t trigger the PAPI to come on at Atlantic. With the knowledge from the book, I flew a stabilized approach and landed on the numbers. My family didn’t really know what was going on, and I purposely didn’t tell them. Had I needed help locating the field, or if I wasn’t familiar with the emergency gear procedure, I wouldn’t have hesitated to ask for help. Since that wasn’t needed, there was no need to risk the distraction of panicking passengers. They obviously knew something was going on, but they had no idea what I was really working through. I’m proud that I was able to stay calm and collected while working logically through the situation. I just kept reminding myself that my #1 job was to fly the plane. Lastly, a few parting thoughts: 1) While we would never take a plane up if we thought something bad was going happen, the reality is there’s always a chance. Complacency kills….do your best to stay familiar with emergency procedures. 2) There is a critical difference between Currency and Proficiency– Even when rusty, it’s not too hard to do the important things when everything is going right…..but being proficient is was keeps you alive when you have the added distraction of things
going wrong. 3) As the saying goes: Plan for the worst and hope for the best. Before you get in the plane, run through a list of “what if’s”, and make sure you have a plan to address them. Again, I want to thank Dan for sharing his thoughts. He made a lot of good points and comments, but none more important than the difference between currency and proficiency. This is a great example of the importance of getting up in the club planes more and shaking off the rust.
Kevin Broderick ATP,CFII and Skyhawk Safety Officer