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AOPA Air Safety Institute, UND study stabilized approach

On the heels of the NTSB’s Nov. 14 release of its "Most Wanted" list of transportation safety improvements that included general aviation loss of control, the University of North Dakota, in partnership with the AOPA Air Safety Institute, announced that it is studying the use of a continuous turning approach or “circular pattern” as an alternative to the traditional “box” or rectangular traffic pattern.

Reduction of in-flight loss-of-control accidents continues to be identified by the NTSB as a most-wanted safety improvement. Working with senior NTSB officials at a recent loss-of-control panel, the idea was formed that UND and AOPA team up to explore how simple procedural and training methodology changes in the landing pattern might improve safety and reduce loss-of-control accidents.

The hypothesis to be studied is that in contrast with a rectangular pattern, a continuous turn from downwind to final may provide for increased stability, reduced pilot workload, and a constant bank angle throughout the maneuver, helping pilots better manage angle-of-attack variances. Additionally, the use of a continuous turning approach has the potential to reduce the likelihood of overshooting a runway during base-to-final turns, a scenario that has resulted in multiple stall/spin accidents due to aggressive corrective maneuvering. Depending on the results of the study, this procedure may serve as a mitigating technique to reduce the likelihood of loss-of-control accidents during the landing phase of flight.

“It’s too early to say for sure if the continuous turn to final method will be a safer, more stabilized way to land. But what we do know is general aviation has been flying the rectangular pattern for decades, and based on substantial loss-of-control accident data in the landing pattern, we believe it’s time to conduct research to determine if there is a potentially safer alternative,” said George Perry, senior vice president of AOPA’s Air Safety Institute. “The U.S. military, commercial airlines, and many airline ab initio programs already utilize the continuous approach turn as the standard to support safe landing pattern operations. We should determine which is safer for general aviation, and this study will help us find the answer.”

“The research will consist of flight data analysis to evaluate differences between the circular pattern and the rectangular pattern,” noted Lewis Archer from UND’s aviation department. “Variables that will be analyzed include bank angle, airspeed, and runway overshoot.” Lewis continued, “Although the study is in its early phases, and it’s far too soon to draw any definitive conclusions, the new procedure has already been studied and practiced by a select group of UND instructor pilots and initial data collection has been going quite well.”

The study is ongoing, and both UND and the Air Safety Institute are hopeful that results will be available sometime in early 2017.

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