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What leads a Cessna 172 Skyhawk on short final to impacting an SUV? The answer might not be as simple as you think.
Millions of errors are committed by pilots each and every year. Some are small, like forgetting a checklist item, but when compounded on top of each other, error chains can lead to increasingly dangerous situations.
The student pilot was returning from a solo cross country flight on November 3rd, 2012 in C172S N985GE when he made an approach to Runway 17 at the Northwest Regional Airport (52F) in Roanoke, Texas. According to the NTSB Accident Report, "he stated that the approach for landing was normal until he was on short final approach, when the airplane's landing gear struck an automobile that was being driven on a road that crossed near the approach end of the runway."
Error 1: "The student pilot's failure to maintain clearance from obstacles on the runway approach path" (NTSB). It seems so obvious to see and avoid cars crossing the approach path to a runway, but how easy really was it for the pilot involved? Let's look a little deeper.
This was a new student pilot. He was focused on making a successful landing on a relatively short runway (3,500 X 40 feet). He was probably focused directly on his aiming point. Sitting in the left seat of the Skyhawk, imagine how hard it would be to see a crossing car below you to the right. In fact, here's what the pilot had to say: "When I turned final, I aimed for the line just after the runway numbers. I checked my speed again and I was at 65 knots. I did not see the SUV because he turned left and drove across my landing path during the short final phase of my landing. The car ended up in my blind spot."
This is the blind spot:
The driver of the car had been down the road before, even noting the position of the road compared to the runway as "precarious." According to the NTSB, "He noted that he did not see or hear the approaching airplane traffic before the accident. He said he was about halfway across the road, immediately north of the runway, when he first heard the airplane engine; the airplane impacted his car immediately afterward."
Error 2: "The automobile driver's inadequate lookout for approaching aircraft before crossing the runway's approach path" (NTSB). He failed to take extra caution, even in a spot that he knew was "precarious" from his previous experience.
Error 3: "The airport management's decision to relocate the runway displaced threshold, which did not provide an adequate safety margin for approaching aircraft" (NTSB).
Just a year before this accident, in 2011, "data indicated that the runway threshold was previously displaced by 400 feet." For a normal final approach, this offered adequate clearance between cars on the road and approaching aircraft. Check out the threshold location from the previous year:
But in 2012, "the displaced threshold for the landing runway was located about 140 feet from the approach end of the runway. The roadway that crossed the extended runway centerline was located about 25 feet from the approach end of the runway pavement, about 165 feet from the displaced threshold" (NTSB). Check out the difference in length below:
This change shortened the displaced threshold by 260 feet, increasing usable runway length for landing. But at the same time, it removed an important safety margin for approaching aircraft. Keep in mind, as a privately-owned airport, management was not required to maintain airport design standards established by the Federal Aviation Administration for safety margins. Warnings in place for drivers were weak at best...
Between the pilot's blind spot (a perceptual error), the driver's inattentiveness (another error), and the airport's decision to lengthen usable runway distance by decreasing the displaced threshold, this accident was a perfect example of an error chain. One error led to the next error, culminating in a dangerous accident in which, fortunately, no one lost their lives.
There are plenty airports out there like this, with roads crossing just before runways. Next time you go flying, make sure to double check for crossing traffic and ALWAYS check your blind spots!
Have you been into an airport like this? Tell us in the comments below.
Swayne is an editor at Boldmethod, commercially licensed pilot with multi-engine and instrument ratings, and a commercial aviation student at the University of North Dakota. He's the author of the articles, quizzes and lists you love to read every week. Swayne's experience ranges from international flights in a King Air F90 to ferrying a 1943 Grumman Widgeon across the country. You can reach Swayne at firstname.lastname@example.org, and follow his flying adventures at http://www.swaynemartin.com.