October 1995 Volume 38 / Number 10
Mooney Safety Review
So, hangar fliers, what have you heard about the Mooney M20-series airplanes? Perhaps that they're hot birds, tough to slow down and tricky to land? The AOPA Air Safety Foundation has completed an in-depth safety review of the Mooney. Previous reviews examined the Cessna P-210 and 182; Piper Cherokee/Arrow series; Beech Bonanza and Baron; and Piper Malibu/Mirage.
Funded by the M. J. Murdock Charitable Trust, with technical assistance from the FAA, NTSB, AOPA, and the Mooney Aircraft Pilots Association, the AOPA Air Safety Foundation looked at the Mooney and compared it with other retractable single-engine aircraft. The comparables included the Beech Bonanza, Beech Sierra, Cessna 182RG, Cessna 210, Piper Comanche, Rockwell Commander, and several other models. The record showed 392 Mooney mishaps, compared to 2,450 accidents involving the other aircraft. The study began in 1982 and continued through 1991.
As usual, we find pilots causing the accident about 75 percent of the time with Mooneys — virtually the same as with the other retractables. The Mooney comes out slightly better, with about six accidents per 100 registered aircraft versus 7.7 percent for the comparison group.
Looking at accidents that occurred under instrument conditions, we found that the Mooney pilots seem to do a significantly better job. The IMC accident rate per 100,000 hours for the Mooney is just a little over half the accident rate of the other retractables (5.91 versus 10.14). It's even better for instrument-rated Mooney pilots on IFR flight plans, at 1.89 per 100,000 hours versus 4.97 for the comparison group. For this group of airplanes, the record proves the adage that you are definitely safer on an IFR plan. Mooney pilots also hold the advantage at night. This is the period when we typically see the accident numbers per 100,000 hours skyrocket. The group as a whole literally goes off the graph we produced in the book, while the Mooney shows only a small increase over IMC accidents in general. The question is, why?
There are some theories. One is that the earlier models all came with a full-time wing leveler — the famous PC (Positive Control). It was built into the aircraft with the idea that, should a VFR pilot inadvertently get into the clouds, this would help to get him out again in one piece. A thumb switch on the yoke is depressed to allow maneuvering. Virtually all the later-model Mooneys came with autopilots, but then so did many of the comparable aircraft.
The other theory is that Mooney controls, being actuated by pushrods instead of cables, are a bit tighter and heavier than those in other aircraft; hence, there is more stability and less problem with a lateral upset. However, this is purely speculative.
The pilots who fly Mooneys and the comparable aircraft are virtually identical in terms of total flight time and time in type. Average total time for pilots involved in serious accidents was around 2,000 hours for both groups. As with all the airplanes we've studied so far, the accident percentages drop rapidly after the first 100 hours in make and model. This validates the airlines' thinking about being conservative with a new captain on board. FAR Part 121 requires that until the captain has acquired 100 hours in type, landing minimums are essentially doubled for IFR flight. Based on the evidence we've seen, this is an excellent voluntary guideline for general aviation.
So what about the hangar stories that characterize Mooneys as being hot on landing? There is some element of truth here, but it relates to how the aircraft is flown — not to anything particularly unusual in the design.
The Mooney wing is clean and has very low drag. This is good because it makes for a fast, efficient airplane. It also means that when it is time to descend and land, airspeed control reigns supreme. During descent we don't have many accidents, because the ground is often a long way away. Because pilots may abruptly reduce power to enhance the downward trek, you might expect a high incidence of cracked cylinders due to shock cooling. But this can't be verified. The availability of speed brakes has certainly helped in this area.
Mooney landings can be more demanding than those of other airplanes. With a Cessna, Piper, or even a Beech Bonanza, the pilot can be 10 knots fast on short final and the aircraft will generally tolerate that sloppiness enough to give you a decent landing. The Mooney gives up speed grudgingly at altitude and will whistle very happily along in ground effect with the power at idle if the approach was made too fast. The flaps are not particularly effective, and forcing the airplane to the ground leads to porpoising — perhaps more so than on the comparable models.
The statistics show Mooneys are involved in overshoots twice as often as the comparable aircraft. The good news is that in the decade we studied, only one pilot succeeded in putting a Mooney down short of the pavement — a unique, if dubious honor. The solution is very simple — learn to control airspeed.
With retractable singles, the leading cause of serious accidents continues to be entanglements with weather, and the Mooney is no exception. Poor weather judgment racks up a staggering 26 percent of accidents in both Mooneys and the other airplanes in the review.
One weather accident attests to the renowned stoutness of the Mooney airframe. A 600-hour instrument-rated pilot obtained an early morning briefing advising of moist, unstable air with broken clouds beginning at 1,500 feet and thunderstorm activity at various locations along the route of flight.
The flight departed at 8:55 a.m. and climbed to 8,000 feet. About half an hour later, the pilot encountered a "heavy layer" of clouds at and below his cruising altitude. He requested and received a descent clearance to 4,000 feet. At 9:26 the pilot called approach control and asked where the weather was moving, indicating that he was in some "rough stuff." For the next 23 minutes the flight encountered areas of violent turbulence that caused substantial airframe damage and rendered several flight instruments inoperative. The flight was eventually vectored to an alternate airport and the airplane landed safely. One lesson learned is that thunderstorm detection gear is essential when buildups are embedded.
Mooneys suffer very few in-flight breakups, even when the pilot doesn't maintain control. The result is sadly the same as with other aircraft; it's just that all the Mooney's pieces are found in one spot. I also have a theory that perhaps some other Mooney pilots will confirm or deny. The M20E that I used to fly was exceptionally stiff in turbulence; when it got bumpy, the only way to avoid becoming bruised was to slow down, thus relieving the stress on the airframe. (The bruises also may have had something to do with worn seat cushions.)
The safety review, in addition to a statistical analysis and comparison with other retractables, has a section on accident briefs. Included is a complete training syllabus for new, as well as experienced Mooney pilots, and a series of Mooney articles that have appeared in AOPA Pilot.
See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is president of the AOPA Foundation.