The Robinson R22 has been widely criticized. Should it be?
The Robinson R22 and its larger sibling the R44, are two of the most widely produced light helicopters in the world. They are relatively cheap to buy, and have low operating costs, making them popular with flight schools, private pilots and law enforcement agencies. They also have a reputation for crashes, but is there something wrong with Robinson helicopters?
Access all episodes of End of the Line on Engineering TV along with all of our other series.
* * *
Episode Transcript:
This small helicopter is the Robinson R22. If you think you’ve seen one flying overhead, you probably have, because something like 5,000 of these aircraft have been built since 1979—and even more of its bigger sibling, the R44.
And it is popular for good reasons: it’s relatively inexpensive with low operating costs, making the aircraft perfect for helicopter flight schools, short range surveillance and policing operations, as well as recreational flying.
The R22 and R44 are also noted for something else: accidents. So much so, that Texas law firm Slack Davis Sanger advertises itself as specialists in prosecuting Robinson helicopter litigation. According to the firm, since 2000 there have been 96 crashes involving Robinson helicopters in the U.S., which resulted in 165 fatalities, with global loss rates of 291 airframes since 1982 with the loss of 512 individuals.
Robinson helicopters are the subject of lots of discussion on Internet boards for professional and amateur rotary wing pilots, and a lot of the commentary is very uncomplimentary. So, what’s going on here?
Well, the Robinson technical service bulletin and FAA enforcement records of Robinson helicopters are not especially noteworthy compared to other rotary wing or fixed wing aircraft, with early accidents attributed to rotorblade delamination. Robinson helicopters are light, especially the R22, and they are noted to be very light on the controls, with an important difference to larger helicopters: a very low inertia rotor system.
In the case of an engine failure, most helicopters can be flown in “autorotation”: performing a safe landing by trading off the kinetic energy of the spinning rotor blades for aerodynamic lift. The process requires that rotor RPMs stay high enough to generate sufficient lift as the ground approaches, and the inertia inherent in any large rotating assembly means that pilots have a little time to assess the situation before taking emergency action.
But not much time.
The combination of small rotor blades and low mass means that light helicopters, Robinson models included, will lose rotor RPM quickly in case of engine failure, necessitating rapid and decisive action by the pilot. A U.S. Army study of the time necessary to enter autorotation at full power and emergency rated the R22 as “poor” although the time difference between models is as little as one second. Generally, heavier helicopters appear to be safer, a statistical fact also common to fixed wing aircraft.
So, are Robinson helicopters dangerous? It’s important to look at how the aircraft are used before making a blanket statement.
You can buy a Robinson helicopter for under half a million, and a used one for half that. Operating costs are little over $400 per hour, which is incredibly cheap by helicopter standards. This means that major operators for Robinson helicopters include flight schools and private owners.
Which cohort is likely to have fewer aircraft hours on type and lower levels of overall training? Students and hobby pilots. So, the combination of a very light aircraft that is very sensitive on the controls, with the pilot skill and ability base that is statistically lower than that for larger, heavier helicopters, and you have a prescription for a higher accident rate.
What’s the aircraft with the most crashes? By far the Cessna 152, followed by the 172. Why? Affordable aircraft, commonly used by private pilots and flight schools.
Interestingly, the Internet is full of comments from pilots who claim that they would never fly in a Robinson R22, even though neither it nor its R44 big brother make even the top 20 in total accident numbers.
To me the real take away is simple: the most dangerous part of any helicopter is the pilot. Therefore, the logical engineering approach would be to keep his hands off the controls as much as possible, then stability augmentation and eventually full automation. This is something the emerging air taxi industry is working hard to achieve. Maybe what we need is the eventual elimination of the weakest link in aviation safety: people.
