Light Retract Safety

This group of six airplanes posts a similar safety record but engine failures among Mooneys and Commanders are a concern.

For owners not blessed with heroic stick-and-rudder skills and cash to burn, the usual sequence of ownership starts with a fixed-gear single and progresses to a high-performance retractable. For many owners, the retract is the end game.

The attraction of a folding-gear single is undeniable. These models are plentiful in both variety and price, most offer good performance at reasonable operating costs and they usually do represent a step-up in performance and capability.

Ignoring price and performance for this analysis, were comparing these aircraft strictly on one narrow parameter: the models accident record. What kinds of accidents do they suffer and how do they compare with each other?

As in the other articles on this ongoing series of safety reports, we make no overarching claims about accuracy. As weve noted many times before, NTSB accident data is, at best, suspect and, at worst, utterly in error. Based on the latest accident data available, what appears here is our best estimate about how these models compare.

How We Did This
First, this obviously isnt all the single-engine retracts on the market. There are so many choices that to keep our analysis contained, weve divided the species into two subsets, light four-place retracts and heavier models, to include six-place designs. Well examine those in a subsequent issue. To a degree, weve also sorted the retracts by price; the group covered here are at the low end of price spectrum.

As in our previous safety reviews, we looked at all of the accidents for these types during the five year period between 1994 and 1998, relying on raw NTSB records for our data. The NTSB sometimes assigns probable cause for accidents and sometimes doesnt. In the interests of consistency, weve assigned our own accident categories when none exist.

The usual cautions apply, which is to say NTSB data is often sketchy and incomplete. Moreover, although the accepted way of establishing any kind of statistical safety comparison is to calculate an accident rate based on exposure-hours flown-the best we can do is an informed estimate.

The relative accident rates for these models was calculated using the estimated hours flown provided by the Aircraft Bluebook Digest multiplied by the total number of each model that appears in the FAA registration records. The average hours-flown numbers are based on price surveys at time of sale and may or may not reflect reality.

Thus, while weve made every effort to make these comparisons accurate, theyre hardly airtight, given the lack of accurate data. We feel it only fair to make this caveat crystal clear.

Cant Anyone Land?
When you think about it, once the gear is down and locked, a light, four-place retractable is not entirely different than a fixed-gear single. When you slap the gear down in a Cessna 172RG, for instance, it doesnt handle much differently than the fixed-gear version.

There are some minor differences, of course. When the gear is down, the Arrow tends to sink a bit more aggressively on approach than does an Archer.

But were not talking night and day differences here. The same cant necessarily be said of the heavier retractables, such as the Piper Saratoga series or the Beechcraft 36 line.

With that observation in mind, the single largest cause of accidents in the retractable realm-with a couple of exceptions-is the same as in fixed-gear airplanes: runway prangs due to loss of control, overruns, undershoots and mishandling in crosswinds.

Three of the models we examined-the 180 and 200 HP Arrows and the Cessna 172RG Cutlass have all most identical percentages of runway loss of control incidents, about 35 percent or so. Thats in line with the average of fixed-gear singles weve analyzed. The Mooney, Cardinal and Commander seem significantly better in this category, with the Commander best of all, posting a respectably low 15 percent for runway loss of control incidents.

Why is this so? Were not sure but we suspect that the Commanders trailing link landing gear plays a role. Commander owners rave about how easy it is to grease one on in the 112/114 series. But in the same breath, some will also complain about the models limited rudder authority, making it difficult to crank in much of a sideslip in a crosswind. But if the data is accurate, lack of rudder authority isnt a significant factor in runway fender benders.

If theres a surprise in this category of airplane and accident, its the Mooney data. With its stiff, unyielding rubber donuts, Mooneys have a well-deserved reputation for porpoising when theyre stuffed onto a runway in a three-point attitude with too much speed. Nonetheless, either pilots dont have as much trouble with this as they do in other models or fewer accidents get reported.

Typically, a serious Mooney wheelbarrow incident results in a bent prop and occasionally landing gear damage or an excursion into the weeds if the hopping gets completely out of hand.

Conclusion: if you want an airplane easy to land, the Commander may be the best choice in this category of aircraft.

As for the gear itself causing accidents due to collapse or general malfunction, this is definite risk. If the gear can collapse, in certain instances it will.

For example, we found 39 accidents involving the Cessna 172RG, five of them were the result of gear mechanical failure of some kind while two appeared to be garden-variety gear-up landings caused by pilot error.

At the other end of the spectrum, we reviewed 148 Mooney accidents, none of which were caused by mechanical failure of the landing gear. Indeed, even when pilots have explored the ditches or trees after losing control on the runway, the gear often stays intact on a Mooney.

Reviewing service difficulty reports for these models, we find more problems with the Cessna and Piper gear-both of which use electric motors to drive hydraulically actuated gear-than we do with the electrically driven system in the Mooney. The Commander also has an electric/hydraulic system. In our last review of the Commanders safety record, we found some gear collapses, but none occurred during the 1994-1998 time frame of this report.

Although we hesitate to call the Cessna gear design flawed, its clear that its more needy of preventive maintenance than the electric systems found in Mooneys and Beech products, which rarely seem to cause trouble.

Engine Failures
One of the difficult-to-explain mysteries in general aviation is why an engine installed in one airframe seems to earn a reputation as being bulletproof but appears to be trouble prone in another aircraft.

That seems to be the case with the Lycoming O-360 used in all of the airplanes we examined for this safety review. We should note that there are many variations of the O-360, both carbureted and fuel injected and the earlier parallel-valve 180 HP version and the later 200 HP angle valve found in the later Mooney and Arrow models.

In general, however, these engines share the same basic construction features and evidently some common weaknesses.

Scanning our admittedly smallish sample, the Mooney and Comanche are near the top of the heap in engine failures as a percentage of total accident causes. More than a quarter of all accidents in these two types are attributed to engine failure of some kind, compared to an average of 12 percent for the fixed-gear singles weve examined.

Acknowledging the NTSBs lack of definitiveness in accident reports, when the narrative says number three cylinder departed the aircraft that strikes us a bonafide catastrophic engine failure and we take notice when these account for a quarter of all accidents.

At first glance, the situation appears even worse for the Commander 112 series, in which engine failure represents nearly a third of all accidents, the highest of any model weve seen. The Commander 114, by the way, is fitted with 260 HP Lycoming IO-540T4B5D while the 112 has the Lyc IO-360 found in the Mooney and the Arrow, although a slightly different variant of it. Worth noting, however, is that the number of accidents in which the Commander was involved in was so small we hesitate to draw meaningful conclusions from our review.

On the other hand, when we read so many accident reports involving engine failure, our suspicions are aroused. In general, engine failure as an accident cause in this group of airplanes averages about 21 percent, considerably higher than the same category for the fixed-gear singles.

On the plus side, both the Cardinal RG and the 200 HP Arrow have remarkably low engine failure stats and there are enough of them flying and enough accident data to draw some general conclusions. For whatever reasons, they appear to have slightly fewer engine failures.

Interestingly, the Cardinal RG and later Arrows and Mooneys all share a variant of the 200 HP angle-valve Lycoming IO-360. The early angle valve was indeed a problematical engine due to an undersize main bearing design and some problems with torque values for cylinders. However, these problems were later corrected and the engine is now considered one of Lycomings best designs.

Stalls and Spins
If weve learned anything from compiling the safety records of various aircraft models, its this: stall/spins as an accident cause are all but a non-starter. Whether due to training or benign handling characteristics of most modern aircraft-probably a little of both-there are too few stall/spin accidents to point the finger at any one model.

We found this to hold true for the retractables as well. Only the Mooney and Comanche had any measurable stats on stall/spin and these could just as well have been mistaken for other causes.

The stall/mush, however, is another matter. The typical scenario for this accident is a low-altitude sink fest on either approach to landing or takeoff resulting in an untimely contact with the terrain or obstacles. These tend to be fatal to a far less degree than are stall/spins, which almost always happen at a higher altitude.

The two Cessnas lead this category of accident, with the Cardinal having 21 percent of its accidents assigned to stall/mush. The Cutlass is right behind it at 18 percent. The early Cardinal had a problem with limited stabilator authority but this was fixed in later models and it really never applied to the RG version.

With 200 HP and a 2800-pound gross weight, the Cardinal isnt exactly underpowered, although the Mooney has a slightly more favorable power-to-weight ratio. The Cardinal does, however, have enormous flaps and both gear and flap extension induce pitch changes that pilots need to deal with.

Although owners complain about gear maintenance, weve not heard widespread complaints about mushiness or a tendency to sink during an approach, but obviously it happens occasionally.

We suspect the Cutlass stall/mush rate is due to its use as a trainer for neophyte pilots stepping up to something larger and faster. Were sure that what appear to be at least some stall/mush incidents are really land short incidents that get mis-characterized. The airplanes with the best stall/mush records are the Mooney, Arrow and Commander, in that order.

Out of Gas; Again
In our estimation, all of these aircraft are more or less equivalent across the board in fuel exhaustion or fuel mismanagement accidents. In general, they seem to fare far better than their simpler fixed-gear cousins in this regard.

For example, the fixed-gear Archer is all but identical to the folding-gear Arrow yet the Archers fuel exhaustion rate is a whopping 25 percent of all of its accidents while in the Arrow, running out of gas accounts for only 10 percent of the total.

Both have essentially the same fuel system, consisting of a left and a right tank with a single switch. We can only guess that the Arrow attracts pilots of more experience and training, something that might be effectively mandated by insurance requirements. One theory is that anytime you introduce a fuel system which allows pilot to select a tank and run it dry, you increase the likelihood of fuel mismanagement or exhaustion. And the more complex the system, the more likely it will cause trouble. That may be true when comparing the Archer with, say, the Cessna 172 or 182, in both of which fuel mismanagement accounts for 7 percent and 11 percent of the total accidents, respectively, while, as mentioned, Archer pilots run their airplanes out of gas more than twice as often as that.

Nice theory but it doesnt hold true among the retracts. The Mooneys and Pipers have only selectable fuel tanks, the Cessnas have a both option which pilots tend to use. Yet theres no meaningful difference in fuel exhaustion accidents among the retracts.

Other Causes
For most aircraft we review with safety in mind, we find three leading accident causes: runway loss of control, fuel exhaustion/contamination and engine failures. On some models-the Grumman Tiger comes to mind-miscellaneous causes will occupy the second or third rank. Occasionally, VFR-into-IMC also scores near the top.

Among the retracts, however, we find VFR-into-IMC appears to be a significant player only for the Cardinal RG. In the Cutlass and Commander, we found no such accidents at all and the Mooney, Arrow and Comanche show a percentage of VFR-into-IMC incidents comparable to trainers and fixed-gear cruisers.

VFR-into-IMC, of course, is more a reflection of the pilot than the aircraft, since anyone can fly any airplane into cloud and lose it. If any of these aircraft could be considered skittish in cloud for the unseasoned IFR pilot, we would guess it would be Mooney, which has a tendency to build speed rapidly if upset. But the numbers dont seem to support that theory.

We did note that the Cessna 172RG has a higher percentage of hard-to-categorize accidents that we can only lump into the other file. These often relate to the creativity of the pilots who use the Cutlass for training operations.

Comparing Rates
Looking at the overall rates among these airplanes, can;t really draw significant conclusions about their relative safety. The Commander 112 appears to have a higher overall and fatal rate than the other models but the calculation is based on only 13 accidents over five years so were reluctant to assign it much weight.

Then whats the good of all this you might rightfully ask? We think the overriding value of this accident study is found in the types of accidents these aircraft appear to get into, not necessarily the rates themselves.

For example, we think its worth noting that in the Mooney M20 series-again, up to and including the 201-engine failure is the most common form of accident. That appears to be true in the Commander as well and in the Comanche, engine failures are the second leading apparent cause.

Checking with shops who maintain these airplanes and overhaul the engines, were told that theres no obvious smoking gun here, no characteristic weak point in the engine that tends to cause failures.

However, we think the data is relatively truthful here and that there are installation factors-oil lines, prop governors, cooling and lubrication issues-that increase the likelihood of engine failures in these airframes. That doesnt argue for not buying them based on that factor alone but it does offer fair warning to pay attention to preventive engine maintenance to reduce the risk.

Among those models where runway loss of control is the leading cause, the take-it-away value is obvious: learn to land the airplane and keep proficient enough to handle crosswinds and contaminated runways.

Also With This Article
Click here to view “Checklist.”
Click here to view “Cessna 172RG Cutlass, Cessna 177RG Cardinal.”
Click here to view “Piper Arrow, Piper Comanche.”
Click here to view “Mooney M20 series, Commander 112/114.”
Click here to view “Rankings by Model.”

-by Jane Garvey and Paul Bertorelli

Jane Garvey is a contributing editor and Paul Bertorelli is editor in chief of Aviation Consumer.