This post is a report from fellow pilot and twitter @matthammer, about an in-flight incident involving the mixture control. The author is a private pilot from New Jersey, working on his commercial certificate and instrument rating. Vincent.
It was a routine cross-country for me, a round-robin from TTN, to MSV, AVP, and back to TTN. The weather was beautiful, winds aloft were practically calm, and, aside from the occasional light chop, it was a smooth ride. The aircraft also seemed to be performing fine — my pre-flight showed no discrepancies, and the run-ups (one at each airport) went without so much as a hiccup. Things turned out to be a little more interesting than I planned on the last leg, though.
After departing AVP I began a climb up to 3000 feet, 1500 feet lower than my planned altitude to avoid an unexpected broken layer. During this climb I noticed the mixture knob felt a little more loose than normal, but didn’t really think much of it at the time. Thirty or so miles later I had cleared the broken layer, and decided to climb up to my planned altitude of 4500 feet. This is when things became a little more interesting.
After arriving at 4500 I went to lean out the engine a bit more. But much to my surprise, after a few turns, the entire mixture knob (including a good 8 or so inches of the cable) came out of the panel and fell on the airplane’s floor. “Wonderful,” I thought to myself. Thankfully my flight instructor had really drilled me on handling various contingencies in flight — so rather than freaking out, I diverted my attention to flying the airplane and assessing the situation. I reasoned that since the airplane was still running smoothly, and I was only 40 or so miles away from TTN, I would just continue the flight. I also decided that if any other adverse situations developed I would get help from ATC (I had flight following from Allentown at the time).
At about 12 miles out I began a gradual (300FPM) power-on descent to TTN’s pattern altitude of 1200 feet. If the engine started coughing, I planned to declare an emergency to Trenton’s tower. Thankfully, the entire descent went without so much as a hiccup. I set up for a right base on runway 24, and landed with a little extra power.
Shutting down the engine actually turned out to be the biggest challenge. Normally you just pull the mixture knob all the way out, which starves the engine of fuel. But obviously that wasn’t going to work, since the knob was currently lying on the floor. So instead I started by turning the master and mags to the off position. That didn’t work, so I pulled the fuel shutoff valve. After (what felt like a minute and a half or so) of sputtering, the engine finally ground to a halt. I finished securing the airplane, checked to make sure there was no way it could be accidentally started, and left to inform the dispatcher of what had happened.
Looking back, I feel pretty confident that I handled it well. I never once felt as if I was pushing things in a way that compromised safety, yet I also managed to avoid the hassles (read: government and media) of declaring an emergency. The incident also reminded me of the importance of training for emergencies. I would rarely go a dual flight without some sort of simulated emergency. Even though this particular situation was not one that I had been trained to handle, my CFI had drilled the emergency handling mindset deep into my head.
When something unexpected happens, the first step is *always* to fly the airplane. Doesn’t matter if you’ve lost your engine, you still have a best glide speed which you need to maintain, and you should be heading for a suitable field to land on if necessary. (You were keeping an eye out for good places to land in an emergency before the engine cut out, right?) Second, you need to assess the situation. Is it an actual emergency? Are you in immediate danger? What’s the most logical thing to do to arrive on the ground in one piece (preferably at an airport, but always be ready to accept that that may not be an option)? If it is an actual emergency, let ATC know (make sure you’re squawking 7700, unless you have flight following — in which case you should give your squawk code to ATC during your mayday call). But either way, after you’ve decided on the best way to handle the situation, COMMIT to your plan. Don’t second guess yourself unless it’s glaringly obvious that you’ve made a mistake. Youíre better off with a mediocre plan started in time, than with a perfect plan started too late.
{ 3 comments… read them below or add one }
Good writeup, Matt. Seems like there were more problems with your airplane than the mixture, though – sounds like your magnetos were screwed up as well. You should, if the P-leads are in proper shape, be able to shut off with the mag switch (though the master will do nothing!
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Glad everything turned out the way it did.
Eric,
I actually meant to mention the P-leads in my writeup… left it out by accident, though. Thanks for bringing it up.
I’m very happy to hear this had a successful outcome and good job remembering to fly the plane and navigate as first and second priorities.
However, I’m concerned about your reluctance to notify ATC of your problem. In your situation I think you should have declared a “PAN-PAN” (urgency) call to ATC – Possible Assistance Needed (not exactly what PAN means, but it’s a good neumonic). This would have alerted to them that you had a problem with your mixture control, and would have made an actual emergency declaration (MAYDAY) less surprising to ATC should it have been required. Wouldn’t it have been good to have at least some level of priority handling? Without notifying ATC early on, they might not be able to move other traffic out of your way. The PAN indicates “possible” assistance needed – there’s no drama if you don’t actually require the emergency treatment.
Note that the phraseology of “declaring an emergency” is not really official, even though it’s widely used in the US – you’re supposed to use PAN-PAN or MAYDAY to specify the urgency level of the emergency.
I’m not sure what the level of papework required for a PAN-PAN call is, but I really don’t think that should be your concern when in-flight. In fact, you should WANT to fill out paperwork, because as a safe pilot, you should be concerned about how the mixture control (and mags) got into that condition to begin with. Creating a paper trail will be hopefully lead to some corrective action so that problem won’t befall a future aviator.
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