March 1, 2005
By Bruce Landsberg
AOPA ASF Executive Director Bruce Landsberg generally has had happy landings.
Landings are easy when you know how. Nobody does. We keep striving but not always successfully, as a recent NTSB study shows.
Based on landing mishaps that occurred in 2000, general aviation could probably do better.
In 2000 there were 478 accidents that occurred in the landing phase of flight. This accounted for roughly 26 percent of all general aviation accidents. Over the past decade it has consistently hovered in the mid-20s. Assuming the exposure is constant, we're not getting worse but we're not improving either. If you assume there are 20 million landings a year, that works out to just over one accident every 50,000 touchdowns. Don't ask me if that's a good number — it's a WAG based on the mixture of cross-country flights, where there is much less than one landing per hour, and pattern work, where there are many more. Despite the relatively low estimated ratio, consider that almost every one involves an aircraft with substantial damage. If you think getting a sport-utility-vehicle bumper fixed after a fender bender is pricey, just ask an insurance broker or maintenance tech what it costs to repair a hard landing.
The very good news is that only nine accidents in this population, just 2 percent, involved any fatalities. That's compared with 20 percent, as a whole, for all GA accidents. The fatals usually occur when the aircraft is going fast and strikes the ground at an acute angle. In landing, the aircraft is traveling slowly, somewhat close to landing attitude, and there are relatively few obstacles to hit close to the runway. In the typical incident after touchdown, control is lost and the aircraft wanders off the runway. The landing roll accounted for 210 accidents and the flare or touchdown for 152.
Pilots tend to be uneasy about crosswinds and for good reason. Where weather was cited as a cause or factor, crosswind was the most prevalent. But if your vision is of the windsock standing straight out like a howitzer, guess again. In almost 90 percent of the accidents where wind information was available, the measured crosswind component was less than 10 knots and in almost 60 percent of the cases it was less than four knots. Most GA aircraft have a demonstrated crosswind component between 15 and 20 knots, so it's not as if the machine won't handle it. We're just not very good at aligning the longitudinal axis of the aircraft with the direction of travel. That's a fancy way of saying the nose isn't pointed where the airplane is going. Proper use of rudder is a bit elusive for accident pilots.
Since it's easy to be judgmental, I should point out that many new pilots get little, if any, instruction in crosswind landings despite what the certification rules say. The reasons are simple: Most lessons take place when there is little or no wind, way too much wind, or where the local runway is aligned with the wind very nicely. At many airports with more than one runway, as soon as the wind changes more than a few degrees everybody switches to the aligned runway. If the pattern is busy the chance to practice the foot, eye, and hand coordination required during a crosswind landing is largely lost. Under those circumstances I've frequently gone to a nearby towered airport and deliberately worked the crosswind runway or found a single-runway airport that afforded the opportunity — even if it took a few extra minutes to get there.
About 15 percent of the accident reports cited gusts as part of the problem, with most occurring when the peak gusts were running between 15 and 24 knots. That is significant wind and can significantly complicate the landing maneuver. For example, a Cessna 172 with a 9,000-hour airline transport pilot encountered conditions that made landing at a grass strip ill advised. The flight was landing to the east and the pilot reported, "The wind appeared to be steady, down the runway. On final approach, wind conditions became choppy, and, on very short final, reducing speed for short-field landing, [the] wind sheared downward. The wind velocity went to zero. Aircraft was forced downward." As the aircraft sank, the pilot added full power and pitched nose up to go around. However, the airplane continued to sink rapidly, caught treetops, and mushed into the ground about 20 feet short of the runway. No injuries.
The runway was about 1,500 feet in length and 75 feet wide. The approach was flown over a valley, with the final segment upslope to the runway threshold on top of a hill. A weather observation at an airport about five nautical miles away showed winds from 120 degrees at 16, gusting to 30 knots. The seven previous hourly observations included winds at 18 to 20 knots, with six of those having gusts at or above 30 knots. As a rule of thumb, when the gusts exceed half the stall speed be very particular about the landing runway in terms of length, width, alignment, and adjacent terrain.
Landing accident pilots tend to be less experienced and there are proportionately more instructional accidents than those that occur in noninstructional flight. New pilots and CFIs spend hours in the pattern and thus have a high exposure to lapses in airspeed and gains in sink rate. Pilots with fewer than 200 hours total time are the most vulnerable and those with fewer than 10 hours in make and model are more vulnerable still. In AOPA ASF Safety Reviews of specific models of aircraft, we consistently find that low time in type is a common accident precursor, with landings being the most common mishap.
Just 2 percent of landing accidents in 2000 involved landing gear up or a gear malfunction. The gear itself was cited in 13 percent of these cases compared to 29 percent for all accidents in 2000.
Those who fly retractables either have made or will make a gear-up landing, according to the lore of landing calamity. I'm not convinced but will find some wood to knock on shortly. Slavish adherence to procedure including before-landing checklists and a short final verification will help. Technology is also a help with power quadrant and flap sensors to remind the pilot in command that if everything else looks like landing configuration (reduced power, full flaps), it might really help the final outcome if the wheels are down. I'd like to see the GPS manufacturers put some kind of warning into their units so when an approach is loaded, or, if flying VFR, when the aircraft is lined up with a runway, the box would nag you with a wheels-down check about one-quarter mile from the end of the runway.
Rounding out the environmental conditions, the vast majority occurred in day VFR with dry runways. Not many landing foul-ups occur on dark, stormy nights. That's likely because not many of us fly in those conditions; those who do tend to be experienced, and are sitting bolt upright in the seat and paying attention.
Does this account for the full picture of landing mishaps? No. These are only the ones that were called to the NTSB's attention. Most of us know of a number of cases when someone had "a deal" at a nontowered airport and the aircraft was quickly and quietly carted off to a hangar for repairs and paint. In many circumstances the incident did not meet the requirements for being reported as an accident, and in others the pilot was just being considerate of the feds, not wanting to burden them with extra paperwork.
As many of us come out of winter hibernation, let's ease back into the air. Get some added instruction and pick your weather and airport conditions carefully. After a few hours logged you'll be ready for a great flying season and some uneventful landings — the best kind!
Safety and Education,
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