Which is the safest single-engine plane for families of four or more? Which airplane should you choose, for transport and pleasure, to keep your family safe?
It comes down to four contenders. Two are “old faithfuls” of general aviation - the Cessna 172 and the Piper Cherokee - with safety records spanning well over half a century. The others - the Diamond DA40 and the Cozy MK IV - are comparative newcomers with shorter but excellent track records.
As an avgeek with stick time in single-engine airplanes, I’m especially interested in safety. It’s my pleasure to guide you through what I have learned.
Airplane safety records can be seriously misleading. The statistics have to be taken in context, before making an informed decision. For example, the raw data show that the league table of crashes by aircraft manufacturer are as follows (as per the Aviation Safety Network):
At first glance, you might think we should all avoid those crash-happy Skyhawks and Cherokees like the plague. Yet, we have come to know and trust their manufacturers to turn out solid, reliable airplanes that have served the aviation community faithfully for decades.
Of course, the secret is to look at the number of accidents in terms of how many airframes of each type are out there, and the hours those airplanes fly. The most popular and ubiquitous private planes are sure to have the most crashes, because they account for most flight hours.
In the case of the Cessna 172, as per NTSB figures, 340 people have lost their lives in Skyhawk accidents, second only (in single-engine planes) to the Piper Cherokee, which has 378 fatalities. However, when we look at the number of Skyhawks in service, the picture changes dramatically.
Crunch the numbers and you’ll find the Cessna 172 has a fatality rate of 0.56 per 100,000 flight hours, leading us to conclude that the Skyhawk is not only the safest single-engine plane in the world, but the safest airplane in the world, period.
Fly her by the book, maintain her properly and adhere punctiliously to the checklists, and your family will be far safer in the Skyhawk than in your car on the highway. But, could there be challengers to the 172’s supremacy in safety?
While not quite as glowing as the 172, the Piper Cherokee’s safety record is 2.01 per 100,000 hours. The cause of most of those fatalities was not a fault on the aircraft. Why do perfectly reliable, serviceable airplanes end up in crashes?
The data show that Cherokee accidents have been caused by inadequate maintenance and pilot error. In one such case, the aircraft’s exhaust manifold was found to be blocked with internally fractured pieces, because of a pre-existing issue that should have been spotted during routine checks.
Other Cherokee crashes have been found to arise from insufficient preparation by the pilot for cross-country flying, and spatial disorientation when flying in a mountainous region in fog.
You can purchase the airplane with the best safety record in the world but, if it is not operated correctly, its safety record cannot prevent an accident occurring. One could argue that the safest single-engine airplane for families is the one flown by a careful pilot.
The family of top-wing Cessnas - the 172 is the commonest - owe much of their safety record to their aerodynamic stability. The center of mass is well below the wings. Coupled with the Skyhawk’s dogged determination to maintain a steady airspeed, that makes her extremely forgiving and easy to fly.
But there is another contender on the scene. Enter the Austrian Diamond DA series, with a remarkable 0.16 fatalities per 100,000 flight hours. That said, the number of Diamond airframes out there is tiny compared to Cessnas, so the figure may change as time goes by.
How has the Diamond come to challenge the venerable Cessna, long-time queen of general aviation safety? To answer that, we need to look at two aspects of airplane safety: active safety and passive safety.
Active safety is all about accident prevention. The Diamond DA40 is a very stable aircraft, despite its low wing. The modern design of the Diamond gives the wing a high aspect ratio, coupled with low wing loading, both of which contribute to stability and flyability.
The aspect ratio of a wing is found by dividing the square of the wingspan by the wing area. A long, narrow wing achieves a high aspect ratio and results in a highly stable airplane.
To calculate wing loading, divide the total mass of the aircraft by the wing area. The DA40’s wing area is large, considering the airframe’s low mass, so the wings are lightly loaded and the airplane is very forgiving to fly.
Thanks to its single-spar construction, with the same crossbeam supporting the wing and the landing gear, the airplane’s center of mass remains low, contributing significantly to roll stability. Like the C172, If no control input is made, the DA40 will tend to level its wings by itself.
Despite the low wing, the DA40 offers excellent all-round visibility, a major contributor to safety. The wing is quite a long way aft compared with the Cessna equivalent. In fact, access to the cockpit is via a step on the leading wing root.
Thus, the low wing does not significantly obscure the pilot’s view of the ground during approach. The low-wing design improves visibility while banking, so the pilot can maintain visual contact with the runway while turning from base onto final when flying a traffic pattern.
The highly efficient wing gives the aircraft very safe stall characteristics. The DA40’s stall speed is low and, if the plane does get into a stall, the controls remain responsive, allowing the pilot to push the nose down and regain much-needed airspeed.
The DA40 has excellent crosswind capabilities. Since a large proportion of aviation accidents occur during take-off or landing, anything that helps a pilot deal with winds on final will enhance safety. Using opposite rudder and aileron inputs, it’s a simple matter to keep the airplane aligned with the runway.
Take-off roll is short and climb performance is impressive, facilitating minimal runway occupancy time and easy obstacle clearance. System redundancy is another major safety feature - standby flight instruments are located above the main Garmin primary flight and navigation displays.
Pilot workload is low and manageable, thanks to the glass cockpit design and excellent autopilot. Therefore, if an abnormal situation arises, you are free to identify and deal with the problem, while the avionics help you maintain safe, level flight with good situational awareness.
All of the above features combine to make an accident highly unlikely in the DA40. But what if it’s a bad day, the holes in Dr Reason’s Swiss Cheese Model align, and we find ourselves in an emergency landing or crash situation? That is where passive safety comes in.
So, despite all the active safety measures, if a crash nevertheless becomes inevitable, what can the DA40 do to maximize your family’s chances of walking away, safe and well? The Diamond has some highly advanced structural tricks up its sleeve.
Once again, consider your car, compared with the ones your mom and dad, or your grandfolks, were driving back in the twentieth century. Early automobiles did not fare well in crashes, because they lacked a reinforced passenger safety cell, a key feature in preventing injuries and fatalities.
Similarly, the Cessna Skyhawk’s elegant, spacious cabin and high windshield are reminiscent of the old horse-drawn coach concept on which the first automobiles were based. In an impact with a high g-load, such a design offers little protection to those inside, disintegrating rapidly and exposing the occupants to serious injury.
Just as in Formula One motor racing, where structural advances have created a reinforced monocoque that makes it possible for drivers to survive horrific high g-force accidents, the DA40 boasts a composite roll-cage structure, resistant to deformation and penetration, providing a secure survival space in the event of a crash.
The cabin environment of the DA40 is crafted to keep occupants’ heads away from rigid structures. The glare shields break away on impact, to minimize the risk of injury. Even the switches are designed with safety in mind, Diamond having opted for non-sharp rocker switches rather than the toggle type.
The DA40’s seat shells are designed to absorb the energy of a crash, and feature anti-submarine plates to prevent occupants moving downward and forward as a result of impact. Non-critical parts of the structure are allowed to fail during a crash, to absorb energy.
An airplane’s safety does not just depend on what the engineers do on the drawing board. The plane’s structural robustness, mechanical reliability, multiple redundancy of systems, aerodynamic stability and build quality are all taken care of before the owner takes delivery. All contribute to safety, but it does not end there.
The most dangerous part of a car, says the old joke, is the nut behind the steering wheel. The same is true for an aircraft. Even the safest airplane in the world can become a death trap in the hands of a pilot who is not sufficiently capable, experienced or careful.
There is a particular brand of automobile, originating in Sweden, whose international owners (perhaps unfairly) acquired a reputation for driving with less than 100% care and attention, because of their faith in the vehicles’ safety systems and crash protection.
It is extremely important, having purchased or leased an airplane based on its excellent safety record, to be rigorous in operating it with safety as your highest priority. That does not just mean while in the air, at the controls. Proper flight planning, fuel calculations, loading and navigation are all vital.
Returning to the Cessna 172, with its enviable safety record, let’s take a look at the causes of the accidents that have happened. Over a two-year period between 2016 and 2018, there was only one Skyhawk crash arising solely from mechanical failure - a stuck engine valve caused partial loss of power.
Immediately after take-off, with a student pilot at the controls, the aircraft failed to climb away properly. The instructor took control, lowered the nose to prevent a stall and landed on the intersecting runway, with just 100 feet of pavement remaining. The airplane came to rest in a ditch.
Among C172 accidents arising from human error, fuel exhaustion did not cause any fatal accidents during the two years, although there were a number of forced landings. In one case, the airplane’s engine had been upgraded. The fuel burn rate had increased, but the pilot had not taken that into account.
In 2012 to 2013, half of the fatal C172 accidents were caused by one of the following errors: flying visually into bad weather and instrument meteorological conditions (IMC), descending to an unsafe altitude while flying IFR, and flying intentionally close to the ground for whatever reason.
More recent C172 accidents have been logged with causes such as pilot incapacitation by drugs or alcohol (around ten percent of accidents), pilots becoming unwell at the controls, and visual problems when flying at night. One Skyhawk crash was caused by the fatigued pilot falling asleep at the controls.
Single-engine family airplanes with rock-solid safety records can quickly become less safe if used in certain ways. An aircraft whose low stall speed contributes to its safety, such as the Skyhawk, also has a comparatively low cruise speed, which increases journey time and adds to pilot fatigue.
Such a situation might arise, perhaps, on a family holiday, when the schedule calls for arrival by a certain time, or else some of the holiday would be lost, and the family may have invested significant funds in the trip. That can lead to a syndrome known as ‘get-there-itis’.
‘Get-there-itis' has caused many aviation accidents over the years. It happens when a pilot becomes fixated on timely arrival at the destination, and starts to prioritize that over safety, which should always be a pilot’s primary concern.
It is far better to land your Skyhawk at an airfield en route, to avoid bad weather or if you are becoming drowsy, than to press on regardless and endanger your family by flying into a situation where you are no longer fit or able to land the aircraft safely.
If a day of a dream holiday is lost, so be it. Provided everyone is safe and well, there will be other holidays. If an air accident occurs, no-one is likely to be able to enjoy any of the holiday, let alone the day you were trying to salvage.
Experience on Type
In one notable Skyhawk accident, a heavily loaded 1976 Cessna 172M with three passengers, just a few pounds below maximum take-off weight, crashed shortly after take-off. The inquiry found that the pilot, aged 19 years, had extended the flaps to 40 degrees. Hence, the aircraft was unable to climb away.
The pilot in that incident had not previously flown the 172. All his prior experience had been on a Cirrus, which required 50% flaps for take-off. Flaps are not normally used for take-off on the 172.
Attempts on world records, such as those involving young child pilots, have caused tragic loss of life and impacted aircraft safety figures. Although the minimum age to become a licensed pilot in the USA is 16 years, anyone can take flying lessons with a qualified instructor beside them.
In April, 1996, a dreadful accident occurred in Cheyenne, Wyoming, when a single-engine Cessna 177B Cardinal, carrying two adults and a child, crashed into a residential street shortly after departing Cheyenne Regional Airport. All three persons on board lost their lives. The 177B is basically a 172 with a cantilever wing.
The subsequent inquiry found that the pilot flying - the instructor - was in the right seat of the dual-control cockpit. The child, who was aiming to fly in stages from coast to coast, with the help of her parents, was in the pilot’s seat in front of the primary flight instruments.
The NTSB concluded that the accident was caused by the instructor pilot’s decision to proceed with the departure in poor weather conditions, rather than defer the flight until the weather had improved. This was, the report added, because of an overly ambitious schedule, driven by media commitments.
In order to monitor the instruments during the initial climb, the instructor pilot would have had to turn his head to the left, swinging back around to the right to get a visual of the ground during the right turn after departure.
With all those head movements, he may have become spatially disoriented, which would explain why he allowed the plane to pitch up excessively in the initial climb. The aircraft stalled in the steep, nose-up turn and, because of the low altitude, was unable to recover.
The lesson learned is that, however admirable an airplane’s safety record, and however well maintained a particular aircraft may be, the moment safety ceases to be the absolute top priority is the moment that a terrible disaster becomes, very sadly, much more likely.
We must not be lulled into a false sense of security by our flight hardware’s reliability and unparalleled track record of safety. The Cessna 177 is a direct derivative of the 172 and we can therefore deem it a safe, trustworthy plane when it is operated properly.
An unusual alternative to conventional aircraft like the C172 and the DA40 comes in the distinctive shape of the Cozy MK IV, a small-scale, 4-seater, single-engine family airplane based on a design by retired American aerospace engineer Burt Rutan. It is available in plan-only form.
Although its owners have to build it themselves, the Cozy is a serious contender for the title of safest single-engine airplane, and I’ve listed it in my top four, for the following reasons.
Although only around 240 examples have been built, the Cozy has only two fatal accidents on file. That is a better safety record than most home-built aircraft. Both the fatal accidents were caused by controlled flight into obstacles: power lines and trees.
The Cozy’s design is unconventional, using foam and fiberglass sandwich construction, with wings attached half-way down the sides of the fuselage. The twin vertical stabilizers and rudders are mounted on the wing tips, with the single propeller at the rear.
Either side of the nose, just forward of the windshield, are two distinctive canards, small wings with leading-edge slats and trailing-edge flaps. The canards generate a proportion of the lift. They also provide highly effective stall protection.
As airspeed falls and the aircraft approaches a stall condition, the first surfaces to stall are the canards, because they are designed to have a higher stall speed than the main wing. This feature is common to all of Burt Rutan’s aircraft designs.
As the canards stall, the nose sinks, increasing airspeed. This has the dual effect of recovering the canards from their stall, and preventing the main wing from stalling in the first place. Thus, the canard design is a very effective safety feature.
The Cozy has one other novel safety feature, protecting the aircraft from being moved by wind while it is parked on the ground. It is interesting to note that the MK IV can achieve this without a conventional parking brake.
Instead of a parking brake, the MK IV’s retractable nose gear can be folded away while the plane is on the ground, lowering the nose to the tarmac, a position known as ‘kneeling’. This also facilitates access to the cabin for the pilot and passengers.
So, there they are - my four contenders for safest single-engine family airplane. Make your choice, fly her as her designers intended, maintain her according to the manufacturer’s instructions, and she will earn her place as a trustworthy and dependable family member.
About THE AUTHOR
After spending years watching every video I could find about flying, I finally scratched the itch and got my pilots license. Now I fly every chance I get, and share the information I learn, here.Read More About Joe Haygood