Accident report: Too many wakes
Did confusion, fatigue contribute to a fatal crash?
The pilot replied that he could accept Runway 16L instead. The controller instructed him to continue for landing—but did not specify for which runway. Nor did the pilot ask for clarification.
It’s easy to see how this scenario could deteriorate. A few more complications turned a dicey situation at Nevada’s Reno/Tahoe International Airport on August 30, 2016, into something much worse.
The tower again radioed with instructions to continue for Runway 25, but “the pilot reported that the airplane was on a downwind leg for landing on Runway 16L,” according to the National Transportation Safety Board, which noted that the controller “acknowledged and, rather than correcting the pilot, instructed him to continue inbound for 16L.”
To the fatigue and confusion, a new risk element was added: “At the time, Runway 16R was being used for landing by two Boeing 757 airplanes in sequence, separated from each other by about 7 miles,” the NTSB report said.
Light aircraft should always give airliners a wide berth in airport traffic patterns, but as you may recall from your ground school study of wake turbulence, the Boeing 757 has a reputation as a wake-maker. It is therefore afforded more separation than comparable-size aircraft.
The controller advised the Bonanza pilot—a veteran aviator who was the co-owner and chief instructor of a local flight school—that a 757 was on a 9-mile final for Runway 16R. ATC cautioned him about wake turbulence and cleared the Bonanza to land. The two parallel runways’ centerlines were 700 feet apart.
The Bonanza pilot said he had “the airliner” in sight—but which one had he seen?
According to the NTSB, the jet on final was 4.5 miles ahead, and lower than the Bonanza. The other 757 was 5 miles away “at its 2-to-3-o’clock position. Given that the pilot’s attention was likely focused toward the runway during this portion of the approach, it is likely that he misidentified the ATC-reported traffic as the 757 on short final, which landed soon after and likely resulted in the pilot relaxing his vigilance in looking for traffic.”
Although the tower now reported winds from 250 degrees at 17 knots, gusting to 20 knots, the Bonanza continued for Runway 16L even though “these wind conditions met or exceeded the airplane’s maximum demonstrated crosswind capability for a landing on 16L, and the airplane was still well-positioned to revert to an approach to Runway 25,” the report continued.
Just after the Bonanza turned base, the second Boeing passed a mile ahead and slightly below it; it was unknown if the Bonanza pilot saw it or “was cognizant of the potential for a wake vortex encounter and the flight path alterations necessary to avoid such an encounter.”
Witnesses said the flight path appeared normal, but “when the airplane was on about a 1/2-mile final approach, at an altitude of less than 200 feet above ground level, it suddenly rolled and descended to the ground.” The 73-year-old, 11,300-hour pilot and a passenger died when the aircraft crashed in a Sparks, Nevada, trailer park, requiring the evacuation of some residents, according to news reports.
The NTSB assigned probable causes, including the pilot’s selection of a landing runway “susceptible to high crosswinds and the translation of wake turbulence across its approach path,” and “the controller’s and pilot’s failure to ensure separation from the B757 and its wake, which resulted in a low-altitude encounter with wake vortices that the pilot was unable to recover from.”
The report discussed at length the communications aspects of the accident sequence, noting that “had either the controller or the pilot specified the location of the traffic once the pilot reported it in sight, that information would have significantly improved the likelihood of detecting the pilot’s identification error.” It added that although the controller had “relinquished” responsibility for traffic separation, this had been done without explicitly assigning it to the pilot.
The pilot’s experience suggested little reason to doubt that he would have been aware of the crosswind condition he faced, or of wake turbulence “behaviors and hazards.”
As for the pilot’s long day of flying, investigators could not assess its effects on his alertness, decision making, misidentification of the conflicting traffic, or what the NTSB described as “vague communications” with air traffic control.
