The pilot reported that, at 17,000 feet mean sea level, the Cirrus SR22’s engine suddenly started vibrating severely and partially lost power. He declared an emergency and an air traffic controller provided vectors for an instrument approach into an airport near Pocatello, Idaho.
The vibrations increased in severity and available engine power was decreasing. He adjusted the mixture and throttle to no effect. He did not cycle the magnetos because he didn’t want to risk losing engine power completely.
After descending through the 2,000-foot broken cloud layer on the instrument approach, he determined that the airplane was not going to make it to the runway. At 1,000 feet above ground level, he deployed the Cirrus Airframe Parachute System, which brought the airplane down into an open field.
He and his passenger rapidly exited the airplane before it was dragged away by the parachute in a 30-knot wind.
Engine data indicated that, 2 hours 56 minutes into the flight, the engine rpm started to fluctuate. Two minutes later, the cylinder head temperature (CHT) of the No. 6 cylinder increased and peaked at 331°F; seven minutes later, it had decreased to 248°F. At this point, the CHT for the No. 3 cylinder increased to 315°F. About 3 hours 13 minutes into the flight, the engine exhaust gas temperatures (EGT) of cylinder Nos. 2, 4, 5, and 6 dropped off while the EGTs for cylinder Nos. 1 and 3 increased.
Examination of the left and right magnetos revealed that the right magneto distributor drive gear had 10 teeth fractured off in the same gear sector, and the left magneto had three teeth broken in the same sector. All of the fracture surfaces on both gears exhibited crack arrest marks and river patterns consistent with progressive fracture.
Based on the right magneto distributor gear damage, it is likely that the failure of the distributor drive gear teeth allowed the magneto distributor to stop rotating in proper firing order and allowed unsequenced repeated firing of the No. 6 cylinder and later the No. 3 cylinder, as reflected by the increase in CHT, which resulted in severe engine vibration and a partial loss of power.
The unsequenced firing of the Nos. 6 and 3 cylinders also precipitated erratic power pulses through the engine that affected the left magneto distributor drive gear, which in turn initiated the left magneto distributor gear teeth failure.
The pilot operating handbook lists the steps the pilot should take in the event of an engine partial power loss. Step seven of the engine partial power loss emergency procedures calls for the pilot to cycle through the left and right magnetos using the ignition switch.
It is likely that, if the pilot had selected the left magneto after the initial indications of partial power loss and vibration, power could have been restored by isolating the right magneto and operating the engine entirely on the left magneto.
The NTSB determined the probable cause as the distributor gear teeth failure of the right magneto that resulted in severe engine vibration and partial loss of engine power, which progressively led to the failure of the left magneto distributor drive gear teeth. Contributing to the airplane’s continued operation with the partial loss of engine power was the pilot’s failure to execute all steps in the engine partial power loss procedure.
NTSB Identification: WPR14FA091
This January 2014 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
It wouldn’t have mattered if he did kill the engine when he selected the wrong mag. The prop would still have sufficient RPM to restart as soon as he selected the good mag. You’re only using one mag when turning the starter or hand propping anyway, you just need that rotation.
To be fair though, it can be easy to forget the obvious in a stressful situation. That is why we have checklists after all. I never cruise as high as 17000, and that seems like a luxuriously long time to troubleshoot.
Amazing at between 17,000 feet and 1,000 feet it never occurred to him to check something that has to be on every piston pilot’s engine emergency checklist. Switch fuel tanks, mixture full rich, fuel pump on, CHECK MAGS, primer in and locked. C’mon folks. But this is my fear with planes like these and pilots like this guy. Ten bucks says he knows the “PFD goes dark” checklist forwards and backwards.
Amazing THAT between…
Let’s really get back to basics and outlaw all general aviation aircraft except replicas of the first bi-wing flown by the Wright Brothers.
Nope………. headline incorrect………….. GRAVITY BROUGHT DOWN THE CIRRUS
So this pilot was smarter and wiser than all those who designed, manufactured and tested the airplane and after much deliberation and staffing of the procedures came up with the required procedure to follow in the event of partial engine power loss. He gets to step 7 in the POH procedure for partial engine power loss and he thinks: “I know better, I’ll not take any chances with shutting down the engine by cycling the mag switch, instead I’ll leave the mag switch on both and keep letting the engine beat and eat itself in hopes it will stay together long enough for me to descend from these lofty heights through the undercast and hopefully, hopefully successfully complete an IAP and landing.”
If the engine had quit when a single mag was selected he could have gone immediately back to both and it would have restarted immediately. He then could have switched to the other mag and found to his delight the engine ran smooth. Unfortunately this pilot choked and proceeded to over think the problem, rejected the POH procedure, all of which increased not lessened his risk.
I like this one for a few reason. First, thanks to Cirrus this guy gets an opportunity to learn his lesson and be a better person. Second, this is another perfect example of how you should USE YOUR GOSH DARN CHECKLIST ALREADY!!
Looking down from 30,000 feet (no pun intended) one would have thought that a rough engine at 17,000 feet over a broken cloud layer shouldn’t necessarily lead to a destroyed airplane. He certainly had plenty of time to trouble shoot the engine and the magnetos are typically a pretty good place to start.
Worst case he should have been able to glide at least 30 miles with a completely dead engine which should have provided for a couple of options.
Obviously, a small fortune worth of computer stuff in the panel didn’t save the day…
This guy had a major engine problem and walked away despite low ceilings.
Well done, sir. Well done, Cirrus.
But if he had followed basic procedures, he would have landed safely and not ruide a perfectly good A/C
John, this may not be true. If he can turn off the bad mag first, then ok. If he kills the good one first, then NO! And based on the description of the failure, I bet you couldn’t restart the engine. You’re welcome to operate with chance, or luck of the draw. Others may prefer to fly with something a little more. I prefer to fly in an aircraft. Not with a keyboard. How about you?
Before the second mag, was damaged, as soon as he hit the good mag, it would have smoothed out, I don’t favor keyboards, much prefer to hand fly all of the time, simply too much tech in airplanes today and not enough touch.
Another one bites the dust, he was TAA trained, managing his TAA systems, but forgot about or more likely had no basic stick and rudder skills, I teach students, first thing with a rough engine, CHECK THE MAGS,
We have too much emphasis being placed on TAA systems and systems management with little or none placed on basic pilot skills, it permeates the entire industry from the heavy metal down. It us killing people ie: Air France 747 and bending airplanes.