Before installing ADS-B, check the transponder. For entry-level replacements, we favor Sandia. For 1090ES, Appareos all-in-one Stratus ESG may be worth the wait.

Our scan of the last 100 Mooney 231 accidents revealed 22 engine power loss events—slightly over half of which were due to something being installed improperly. In most of the remainder, the cause could not be determined.

The 10 runway loss of control accidents were slightly below what we expect to see for nosewheel airplanes. However, about half of them were initiated by pilot induced oscillation events following a bounced landing—a high number. We also noted that virtually all of the accidents on go-arounds came about after the pilot had gone around because of PIO. With more than 15 accident chains that started with PIO, we think avoidance and recovery training is a good idea.

Only four accidents due to stalls isn’t bad—two occurred on short final for landing and the circumstances of the other two led us to think that airframe icing was involved.

As is expected of retractable landing gear airplanes, a few pilots forgot to extend the gear. While a gear-up landing generally does not meet the NTSB’s defiintion of reportable accident, four were reported. Unexpected good news was the almost total absence of gear collapse events—we found one report of a left main gear folding during rollout.

We did find one pilot who, sadly, managed to be the subject of two reports. After landing gear up, he pulled the damaged three-blade prop off of his modified 231. He provided a two-blade prop to the mechanic, who installed it and discovered the spinner would not fit. The mechanic refused to sign the airplane off for return to service. Another mechanic did an engine run and some homework, and found that the prop was not approved for the installation. He refused to sign off the airplane. The pilot then decided to ferry it elsewhere for the remaining repairs. Not long after takeoff, the prop came apart, tearing out five of the six retaining studs. The report stated that the engine-propeller combination was subjected to a “severe spectrum of cyclic loading.”

Ten pilots either ran out of fuel or didn’t select the tank that had fuel in it. That’s about par for the course for airplanes that can only draw from one fuel tank at a time.

There were two inflight breakups. In both, reconstruction of radar data showed the pilots were flying well over redline.

We noted eight events that were pretty clearly spatial disorientation—all of the pilots were instrument rated. Two lost it on climbout on a missed approach. One pilot took off when visibility was but a quarter mile and the ceiling 100 feet. He got almost 350 feet above the ground before entering a descending spiral.

Two pilots continued descending on instrument approaches hoping to see something, and hit the ground. Four pilots tried to fly VFR in IMC and found they could do so for only a limited time.

A lineman fueling a 231 asked the pilot if he was going to remove the ice coating much of the airplane. The pilot said there “wasn’t enough to make any difference.” He and his passenger crashed shortly after takeoff.

A fire and explosion rocked a 231 shortly after a pilot had the FBO plug a 28-volt start cart into his airplane’s 12-volt system.