The pilot reported that, while flying the experimental Titan T-51 Mustang in the traffic pattern at the airport in Lancaster, California, the engine experienced a total loss of power.
He quickly attempted an engine restart, but was unsuccessful and decided to land on a nearby road. The airplane landed hard and the right main landing gear collapsed. The airplane subsequently veered to the right and hit a sign.
Post-accident examination of the engine revealed that a loose magnet in the flywheel struck the attachment bracket for the primary and secondary ignition, which disrupted the timing of the ignition system and rendered it inoperative. The engine subsequently experienced a total loss of power.
Probable cause: A total loss of engine power due to the separation of a flywheel magnet, which impacted the attachment bracket for the primary and secondary ignition and disrupted the timing of the ignition system, rendering it inoperative.
NTSB Identification: WPR16LA149
This July 2016 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.
This accident is an example of the risks in using an auto conversion and that the engineering the reliability of the electrical and fuel systems is critical to reliable operation, as well as the psru.
The exact engine was not identified, but an ignition timing magnet came loose but the electrical component was not protected from this primary failure.
The report didn’t say it was an auto engine conversion. If it was a Rotax version, those are aviation specific engines. The problem was that the engine suffered a total loss of power, for whatever reason, which is a common problem to even aviation engines. That is why pilots should always be ready for an engine failure and be planning ahead. Many aircraft engine failures, even certified engines, can be attributed to a single point failure; a broken crankshaft, dropped/ stuck valve, loss of a cylinder head, failed carburetor linkage, etc., and whether or not it is a redundant system is irrelevant at that point. That this particular engine had this particular problem and knocked out a redundant system doesn’t sound like a common problem, and may be an anomaly. A magnet coming loose from a flywheel is pretty rare. However, people that own those particular engines should be made aware of the potential for that problem occurring and inspect the flywheel magnets on a regular basis.
As far as the reliability of auto engines, many run hundreds of thousands of hours with only regular minimal maintenance, in some of the worst environments imaginable and with very few failures, given the complexity of the engines. I don’t knock automotive conversions because some of them are pretty good, if they are well thought out. Also, many of the advancements in certified aircraft engines came from the automotive world and were adapted to aviation use.
check the FAA N-number registry..
http://registry.faa.gov/aircraftinquiry/NNum_Results.aspx?NNumbertxt=5103
The engine is listed as an AMA/ERPR, a non-certified engine.
3 auto conversions are listed on the Titan T-51 website….
Auto engines used in automobiles do run 5,000+ hours [ not hundreds of thousands ] , but usually are operated at 10-15% of rated power….an easy life.
When used in an aircraft, the power levels are more like 50-70% power, which puts huge thermal stresses on them. Cooling is a major problem with auto conversions.
then there is the psru to get all that auto HP to the prop, and all the torque reflection back to the crankshaft.
No mention in the NTSB report of which engine model was used, since there are several that Titan puts into the T-51. It would be good to know so that others that may have used that model of engine could do a periodic inspection to determine if they may have the same problem about to occur or maybe determine a fix. The assumption that I’m making is that since the engine was a dual ignition engine, it was the Rotax 912, 914, or 915 series. I don’t think the Honda or Suzuki V6’s have dual ignition.
Once again a single point failure takes out a “dual” ignition system in an experimental engine. Ouch!
A single shaft drives the IO540K1G5D/s two magnetos. It is called a suicide engine for this reason.
Oh, and that Lycoming Engine is Certificated. It is the engine used in the Piper Lance and if i remember correctly the Cherokee-Six 300 both are certificated airframes.
B737-400 original engines would self destruct at some altitude above FL300 if I remember correctly. Those were certificated engines. And they proved that a bench test of an engine was insufficient — an engine that was certificated was then modified for the B737-400 — so they weren’t required to be test flown. But actual application resulted in at least three of them failing in flight.
Now they all have to be test flown before certification if I understand the results of the various inspections of the fatal crash (more than one pax killed) and emergency landings (because one engine self-destructed in flight).
Sometimes we have to prove the design. That is part of the risks one takes when using a non-certificated engine.
There are several Lycoming engines with single drive dual mags. The O-320H2AD that is used in the Cessna 172N comes to mind. I wouldn’t have one.