Why Business Aviation Has A Higher Risk of Mid-Airs
Editor's note: This is the first article in a series about mid-airs.
There are many operational, environmental and human factors that synergistically combine to expose the gaps in the flawed “see and avoid” collision avoidance concept that was originally used for the separation of sea vessels. It is no surprise that mid-air collisions continue to occur given the known limitations of the human eye and perceptual systems for detecting another aircraft’s motion on a converging course.
According to Dr. Craig Morris of the Bureau of Transportation Statistics, each year there are an average of 15.6 midair collisions in U.S. civil aviation. Permit me to point out that the 15.6 mid-air-collisions per year are just the proverbial “tip of the iceberg.” We truly don’t know how many near-mid-air collisions have occurred but haven’t been reporte--or the pilots simply didn’t see each other even though their aircraft were perilously close to bending metal.
It is entirely possible for an attentive flight crew of a business aircraft performing their duties to experience a mid-air under these factors. Business aviation’s best professionalism was displayed by NetJets pilots Annette Saunders and Mitchell Marchant who were subsequently recognized for their actions in the aftermath of a mid-air involving their Hawker 800XP with a Schleicher ASW-27-18 sailplane near Minden, Nevada. The Flight Safety Foundation’s Professionalism Award is rarely given, and only to those who exhibit the highest degree of aviator professionalism under extraordinary conditions.
On Aug. 28, 2006, Saunders and Marchant were busy completing the many tasks required while on descent when their aircraft was cleared by air traffic control from 16,000 ft. to 11,000 ft. on arrival into Reno. Oakland Center transferred the flight to Reno approach control just prior to the collision. Marchant, who was the SIC and PNF for the flight, looked down to change the radio frequency. Saunders noted something out of the corner of her eye to the left. As she looked to the left, she noted a glider filling the windshield. She abruptly moved the control yoke down and to the right in an attempt to avoid the glider, but to no avail. The pilot of the ASW-27 sailplane had just entered a 30-degree left bank spiraling climb, whereupon the Hawker jet violently impacted the right wing of the glider near the outboard wing joint.
Saunders suddenly had a gaping hole in her instrument panel blasting 300 knot air straight into her face. She was temporarily blinded by debris from the shattered instrument panel. The flight crew had NO instruments. From their seats they couldn’t see that the nose of the Hawker was completely gone, as well as a significant portion of the leading edge of the right wing. The debris from the right wing caused the right engine to fail, but Saunders and Marchant had no way of knowing this because they had no engine gauges. Unable to maintain altitude and with no gauges to help them determine the airspeed of the aircraft, Saunders and Marchant safely maneuvered their badly damaged aircraft for an emergency gear-up single-engine landing at the Carson City airport.
Miraculously no one was fatally injured. Even the sailplane pilot managed to avoid serious injury by popping open the canopy and leaping overboard from the out-of-control glider and pulling the ripcord on his parachute.
The glider was equipped with a transponder; however, the pilot did not turn on the transponder because he was only intending on remaining in the local glider area, and because he wanted to reserve his batteries for radio use.
Business aviation often operates in airspace that is congested with general aviation aircraft. In this case, the Hawker was descending on an IFR arrival routing that is heavily used by the busy soaring operations at the Minden gliderport. Soaring enthusiasts from around the world converge on Minden because of its famous soaring conditions that allow sailplane pilots to achieve high altitudes and long-distance cross-country flights to qualify for soaring’s prestigious “Diamond” awards.
The flexibility of business aviation means that we regularly utilize satellite airports rather than the metroplex airport serving scheduled air carriers. These satellite airports serve a wide variety of general aviation to include flight schools, charter operations and aerial tours. The traffic patterns at these satellite airports can be hectic, and all of this traffic is compressed under the adjacent Class B airspace. The traffic mixture can include everything from Stearmans giving aerial tours to student pilots practicing touch-and-goes and Robison R-22s simultaneously practicing autorotations, all in the same traffic pattern.
Busy Cockpit Workloads
The workload of fast-flying business aircraft on departures and arrivals is significant. During descent this includes performing the descent checklist, actively managing the energy of the aircraft to prevent arriving at the final approach fix too high and/or too fast, double-checking entries into the FMS to assure they would complying with the altitude and speed constraints on the arrival procedure, properly complying with ATC amended altitudes by following the altitude awareness procedures (requiring both pilots to cross check and confirm with each other), making certain that aircraft systems are properly configured for landing, informing the flight attendant and passengers of imminent landing and to fasten their seat belts, contacting the FBO or ramp for gate instructions, listening to the ATIS to get the latest weather information, double-checking that the assumptions made in their Landing Performance Assessment were still valid, listening to the ATC frequency to maintain their situational awareness on other aircraft or other flight crews reporting potentially dangerous wind shear. My apologies if I left anything important out, but most of the studies done on pilot detection of converging flight paths with other targets haven’t taken into account the excessive workloads of required cockpit duties during these busy phases of flight.
By the way, these workloads coincide with passing through airspace with the highest congestion of other aircraft.
Does this cockpit workload detract from the amount of time that flight crews spend on outside visual scanning? Absolutely. A research study of automated flight deck crews co-sponsored by the NASA Human Factors Division at Ames Research Center, United Airlines and the Airline Pilots Association found that the normal cockpit duties during approach resulted in flight crews detecting another aircraft on a converging course less than 30% of the time. This detection rate plummeted to nearly zero when flight crews were given a late-minute change of runway instructions and/or report of a meteorological change that required their attention.