My wife’s lovely voice pierced an almost-as-lovely evening flight. “What’s that red light on the instrument panel?”
She was pointing to the alternator fail red warning light. And now a fancy-free evening above central Virginia pine forests had just turned into “a situation.”
My wife is competent, cool under pressure. If she ever deigned to get her license, she’d make an excellent pilot. For the time being, she is content to be my First Officer. That’s why after but a moment’s thought I decided it was okay for her to look for the “emergency” checklist for alternator failure while I flew us closer to our destination.
It turns out there is no checklist in the Cessna 172N Pilot Operating Handbook for the particular kind of trouble we encountered. The only two electrical malfunction checklists in the Emergency Procedures section were for “Over-voltage light illuminates” and “Ammeter shows discharge.”
We tried to troubleshoot. Did “alternator fail” mean the belt driving it broke? Did it mean it had exceeded its service life? Had a bolt holding it on to the motor shear off, precipitating an even bigger problem? We assessed our situation. The motor continued to thrum. The plane continued to fly. And the sun continued to set.
My wife agreed that my idea to run both checklists made sense. So we did. The first checklist complete, we determined we weren’t in an over-voltage condition. Good deal because that would have been the more severe of the two electrical malfunctions. We ran the second checklist and… the cabin lights, panel lights, even the landing lights, were dimming rapidly. That’s when we realized our alternator was no longer providing the aircraft’s electricity. The battery was draining.
I calmly laid out our options. We decided that the best one was to press on. We were 30 minutes out from our destination. A mechanic worked at that field, our car was parked there and sunset was also 30 minutes away. That gave us about a five-minute cushion of twilight to get on the ground before the sky went completely dark at dusk. We could make it.
I confirmed our track on the Garmin 430 before shutting it down, along with the radios and all the lights. I felt good. I imagined myself in the first days of air mail, racing the sun in my primitive cockpit, keen to arrive at my last destination. I don’t know what my wife imagined. When I glanced at her, I found her asleep.
I stayed calm until we approached our destination. Tailwinds got us there earlier than planned. Good news. The bad news was that I’d failed to take into account the mountainous ridge west of the airport.
That higher horizon brought sunset sooner than anticipated. I switched on the radios, listened to AWOS and then asked for traffic advisories over the Common Traffic Advisory Frequency. A couple of folks were in the pattern. Most importantly, I’d have to fly a standard pattern.
For some reason, that kicked my brain into overdrive. At that moment, it didn’t matter to me that there were pilots doing pattern work. All that calm from 30 minutes ago escaped out the window. Each second of darkening sky amplified the urgency I felt to get my wife on the ground safely.
So what if I inconvenienced a handful of pilots foreign to me? I announced a “no electrical” emergency and my intentions to make a 5-mile straight-in approach to the downwind runway.
That’s when one of those pilots wondered aloud if a straight-in was really necessary if I could see the field and the runway lights? That question snapped me out of my momentary panic. I could see the field clearly. I could see the other planes clearly. And I could clearly see I was in no imminent danger. I corrected course, thanked the unseen pilot and set up for a 45° entry to the downwind. We landed uneventfully.
I think the reason I almost turned a simple abnormal situation into a fiasco came from overthinking.
Overthinking exacerbated another couple’s flying situation, too.
According to a recent report to NASA’s Aviation Safety Reporting System, two pilots — a husband and wife — and a third passenger were in initial descent to their destination airport. The weather was VMC with 10 miles visibility and light winds.
At 2,500 feet, the husband, a 414-hour private pilot, retarded the throttle of his C172RG but got no corresponding reduction in power. He cycled the throttle a few times. Still no response. He determined he had a throttle stuck in the full power position.
At this point, he asked his wife, a 168-hour private-pilot, to search the Pilot Operating Handbook for an emergency procedure for this situation. Finding none, the couple decided to troubleshoot the problem.
They found no onboard mechanical fix, so they assessed their situation. They were within 25 miles of their destination, in congested, residential terrain. They knew the 3,000-foot destination field well enough to choose it over an alternate with only 10% more runway. The couple chose to ignore larger airports in Class B Airspace farther away. They decided their plan would be to make a power-on approach and landing at their original destination airport.
As the couple approached the airfield, the pilot extended the landing gear and 15° of flaps, which helped reduce the plane’s airspeed to 115 knots. However, except for the retractable gear, a C-172RG operates very much like a fixed-gear 172. So the couple needed to slow to 65-70 KIAS to operate full flaps and land safely. Stuck at max power, they were prevented from slowing down or using more than 15° of flaps. Given their circumstances, they figured they should rehearse the landing attempt.
At 15 miles out, and then again at five miles out, the wife contacted UNICOM, advising all on the frequency of their situation and their intentions. The couple then flew their modified pattern, at flaps 15, 115 KIAS, twice.
On the third go, they decided to land. The pilot cut the motor on final. The plane touched down at 105 knots. Suffice it to say the RG quickly ran out of runway. The pilot veered into the grass to avoid running off the runway. The plane came to rest on a public road, where traffic had stopped to yield to it. No injuries were reported, but the plane’s propeller was ruined when it struck a taxi light.
Post-incident, an A&P examined the throttle cable. The nut on the bolt holding the end of the throttle cable was missing, and the cotter key that normally holds the nut in place was also gone. That’s why the cable became disconnected from the throttle, with the spring holding the throttle in the full power position.
This pilot duo thought they had put together a great plan. But judging from the NASA report, it appears they overthought it. As the reporting pilot wrote:
“The procedures in this case were, literally, invented on the fly. Three times normal landing distance was inadequate in this scenario, due to the lift generated by excessive landing speed and brake ineffectiveness. Diverting to a runway at least five times or even six times landing distance is suggested, if possible. This can be a difficult decision when fuel flow rate is unknown and potentially significantly greater than normal.”
Yet, as my instructors drilled into me and as I drill into my students: An engine you can’t control is an uncontrollable engine. And what do you do with an uncontrollable engine, boys and girls? You shut it down before it shuts you down.
The pilot wrote: “Decision was made to keep the engine running, due to the heavily populated area, in an attempt to avoid misjudging the distance and crash landing short among houses, as well as giving the option for a go-around…”
Remember RUAC from your initial instruction days? Rote, Understanding, Application and Correlation.
Correlation is the highest form of learning. It’s associating what you’ve learned and adapting it to your current, unfamiliar situation. How many times, during a BFR or a recurrency check has your instructor simulated an engine failure while in the pattern? What did you do each time? You used rote, understanding and application to perform a successful engine-out landing.
Had this couple assessed their situation differently, they might have recognized a correlation between their prior experience (simulated engine-outs in the pattern) and their current, never-before-seen situation (uncontrollable motor). Having made that correlation, they might then have devised a safer, simpler solution. But they did not make that correlation. Like I had, they’d overthought themselves into a more dangerous option.
Had they realized that a motor stuck at full throttle could be treated like an engine failure, they could have set up for a normal, 45° pattern entry to the airport, shut off the motor while on the downwind and performed a familiar dead-stick landing.
Had they done that, there’s a good chance their landing would have been less costly and less embarrassing than the prop-striking, traffic-stopping one they managed to survive.