Squeezing more planes into less space (and using technology to keep them apart) may not be as safe as proponents of Reduced Vertical Separation Minima (RVSM) claim. Peter Ladkin, a computer scientist specializing in “dependable systems” at Germany’s University of Bielfeld told NewScientist.com that reducing vertical separation from 2,000 feet to 1,000 feet doesn’t leave much wiggle room for pilots who have to take evasive action when their collision avoidance systems go off. In fact, he claims Eurocontrol, the pan-European air traffic control organization, ignored several incidents and accidents involving sudden altitude changes when it compiled its safety research. Eurocontrol officials deny Ladkin’s claim, saying the ability of modern aircraft to maintain their height precisely keeps them safely separated. Ladkin says the planes themselves may be models of precision but when things go wrong — and humans have to take over — all that accuracy goes out the window. He said he’s particularly concerned about the reaction of pilots and controllers to the warnings issued by the Airborne Collision Avoidance systems (ACAS) on newer aircraft. Ladkin cited three mishaps, a midair collision and two near-collisions, in which the 1,000 feet clearly wasn’t enough. “I don’t think we yet understand the behavioral side of ACAS interactions well enough to guarantee safety under RVSM,” he said. Eurocontrol maintains that the collision rate resulting from RVSM will be one every 150 years but Ladkin says that’s optimistic, given the holes he found in the supporting data.
RVSM May Not Be Safe
Key Takeaways:
- Computer scientist Peter Ladkin argues that Reduced Vertical Separation Minima (RVSM) may be unsafe, claiming 1,000 feet separation provides insufficient room for evasive action or human error, especially when collision avoidance systems (ACAS) activate.
- Ladkin alleges that Eurocontrol's safety research supporting RVSM is flawed, having ignored several incidents and accidents involving sudden altitude changes, a claim Eurocontrol denies.
- Eurocontrol maintains that modern aircraft precision ensures safe separation under RVSM and refutes Ladkin's claims regarding overlooked data or overly optimistic collision rate predictions.
- Ladkin expresses particular concern over the unstudied behavioral aspects of pilot and controller reactions to ACAS warnings under RVSM, citing specific mishaps where 1,000-foot separation proved inadequate.
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