October 1994 Volume 37 / Number 10
PA-28 Safety Review
If you could pick a family of airplanes universally described as easy to fly, the Piper PA-28 series would be a top contender. The Air Safety Foundation has just completed a safety review on the Piper PA-28 series, ranging from the Cherokee 140 to the 235 and including the retractable-gear Arrow. It was the fourth study in a continuing sequence of popular aircraft. (Earlier reviews looked at the Cessna P210, 182 Skylane, and the Bonanza/Debonair series. These are available from the foundation.) Our purpose was to provide an in-depth look at where pilots have experienced problems, how the Pipers compare to similar aircraft, and provide suggestions based on the accident record.
The comparison aircraft for the fixed-gear PA-28s were the Beech 19, 23, 24; Cessna 172, 182; and the Grumman AA-5. The retractable Arrow went up against the Beech Sierra; Cessna 172RG, 182RG; the Rockwell Commander 112, 114; and the Mooney M20.
Using the National Transportation Safety Board's standard of measurement, accidents per 100,000 hours of flight, both the fixed gear and the Arrow had slightly lower total-accident rates than the comparable aircraft. The fixed-gear Cherokees came in at 6.86 accidents versus the comparables' average of 7.28 — not a big difference. The Cherokees did have a higher serious-accident rate at 2.45 versus 1.86 — again, not much difference.
What is perhaps more interesting is that the Arrow had nearly 25 percent more total accidents than the fixed-gear Pipers. There is practically no difference between the Arrow and the other retractables aside from performance and complexity. Our speculation is that the more complex aircraft creates a higher work load. That translates into more distraction and, therefore, more accidents.
Before you jump to the conclusion that there were a lot of gear-up landings or inadvertent retractions with the Arrow, remember that Piper designed an almost goof-proof gear retraction system that was airspeed based. If the speed got too slow, the airplane figured you had to be landing and automatically extended the gear. Similarly, on landing rollout and takeoff, if the speed was below a reasonable climb speed, the system refused to allow retraction unless an override mechanism was used. As a result, only five accidents out of 85 landing mishaps had anything to do with the retractable nature of the landing gear. That's an excellent record, but not much different than that of the Cessna 172RG, which has no such auto extend system.
As with every other aircraft we have studied so far, pilots were the leading causal factor in accidents. In Cherokees, pilots did the deed about 83 percent of the time, while in the Arrow, the pilot-induced rate was 70 percent. There was no difference compared to the other fixed-gear aircraft, but Arrow pilots fared a little better than the comparable retractables which tallied a 76-percent pilot-factor rate.
For reasons unknown, the instrument-rated Piper pilots were involved in a few more accidents on IFR flight plans than the comparison group. The rate was 2.01 per 100,000 hours for the fixed-gear Cherokee and was almost double, at 3.96, for the Arrow. This difference seems to suggest that complexity increases the probability for problems or, maybe, the likelihood that the Arrow pilot will launch into weather that the fixed-gear pilots would not.
There are two areas where fixed-gear Cherokee pilots have significantly more trouble than those in the comparable fixed-gear aircraft. The accident rate involving both instrument meteorological conditions (IMC) and night flights is poor. It exceeds the IFR rate shown above by at least five times. This has nothing to do with the aircraft as far as we can tell and everything to do with the type of pilots flying them. A possible explanation: Cherokees are generally flown by pilots of lower experience than, say, a Cessna 182. They are, perhaps, deceptively easy to control — until an untrained pilot gets into IMC and proves the reasons for getting an instrument rating are absolutely valid. Non-rated pilots fare very poorly in IMC and at night when confronted with marginal conditions. This has been true with every aircraft we have studied so far.
Almost two thirds of the pilots were not rated for the foray into the clouds. Sadly, nearly 90 percent of weather-related accidents involve fatalities, and the Cherokee, for all its gentleness, is not exempt from the laws of physics.
Pilot experience is an excellent predictor of accident involvement. Looking at serious accidents, both the Cherokee and the Arrow peak around 200 hours total time. The pilot's time in type is also an excellent predictor. Make it past the first 100 hours, and the odds of being involved in an accident drop off significantly. Before getting too comfortable with a fat logbook, however, note that in Section Two of the report where individual accident briefs are reviewed, a pilot with nearly 6,800 hours total time and 1,000 hours in type fell victim to complacency. His error was in attempting an instrument approach below minimums and letting the aircraft get so slow that it stalled into the approach lights. Even the docile Cherokee will eventually bite if provoked.
One thing that our database does well is to dispel the myths that grow during hangar flying sessions. You might suspect that the fixed-gear Cherokees have a far greater involvement in fuel starvation than the comparable aircraft. After all, the comparable Cessna 172 and 182 have a "both" fuel position that can be ignored until all the fuel is gone. The Pipers' fuel selector must be switched several times during the flight. Fuel starvation occurs when there is fuel on board but the pilot doesn't figure out how to get it to the engine. There is a 1.2-percent higher involvement of the Cherokee in this type of accident — hardly the stuff of good hangar tales. In the grand tally of aviation statistics, this one isn't going to make the record books.
You might also believe that the Arrow is a good instrument platform, and it is. But it is involved in double the IFR approach accidents compared to the other retractables. Why? There could be any number of reasons, but my speculation is that the Arrow is flown by less experienced pilots since it frequently functions as the transition retractable. In serious accidents, the Arrow pilot total flight time is about one third fewer hours than the comparable aircraft pilots. Before you hasten to change brands based on this number, understand that we are only talking about 14 accidents for the Arrow over a seven-year period. Does this make a definitive case? You be the judge.
Included in this Piper PA-28 Safety Review, beyond the overall safety analysis of the Pipers, are briefs on many different accidents and a section on disorientation. A complete training syllabus is included for transitioning pilots and those wishing for a thorough refresher. A series of articles from AOPA Pilot magazine on the Cherokees is also included, dating to 1961.
If you fly or instruct in the PA-28 series, this 150-page report is a worthwhile investment to learn the true safety picture of this well-liked aircraft. The report can be purchased from the Air Safety Foundation for $22.95 (includes shipping) by calling 800/638-3101.
See also the index of "Safety Pilot" articles, organized by subject. Bruce Landsberg is executive director of the AOPA Air Safety Foundation.