Almost right


By Lex, Posted on January 14, 2007


Something got lost in the San Diego U/T’s lurid reconstruction on today’s front page of last year’s mid-air collision over La Mesa:

Computer alarms flashed and beeped at air traffic controllers for 51 seconds before two small planes collided over La Mesa last February, but the controllers never warned the pilots…

According to FAA regulations, oral warnings are the primary purpose of the air traffic control system. Controllers have standing orders from the FAA to “give first priority to separating aircraft and issuing safety alerts.”

Which is true as far as it goes, but it doesn’t quite go far enough, unfortunately.

Lumping this tragedy with the other cases referenced in this article – including two mishaps in which aircraft under positive control were allowed to fly below their minimum vectoring or minimum en route altitudes in mountainous terrain with sadly predictable results – is misleading, although probably not intentionally so. What the article’s writer neglected to mention is that FAA controllers are only required to separate participating traffic, or those operating under Instrument Flight Rules, in other words. Aircraft being operated under Visual Flight Rules, as the Cessna 182 was in this case, are responsible for their own collision avoidance. The Cessna 152, operated by a student pilot and his instructor was on an IFR flight plan but while controllers may provide routine separation advisories to mixed IFR/VFR traffic, they are not required to do so.

Or at least, that was true until 8 February 2006, the date of this mishap, when the FAA issued a directive to controllers to issue safety advisories to all aircraft in their airspace. Which should be an interesting challenge, given the volume of air traffic just outside the boundaries of Class B airspace and seems to have been locking the door after the horses got out, at least for these three folks. It also sounds like the consoles the FAA are using for safety advisories also need some serious re-engineering from a human factors standpoint: The warning signals generated in high density traffic areas are often lost in the clutter even when controllers aren’t overexposed to a high false alarm rate.
This does highlight another flaw in the general aviation world, at least from my point of view. While a transponder equipped jet aircraft like I spent most of my time flying can quickly get above all the VFR traffic by climbing into the Class A airspace above 18,000 feet – where an IFR flight plan is de riguer – most bug-smashers spend most of their time operating under VFR see and avoid rules. The student was practicing IFR procedures, meaning he was most likely wearing a “hood” to prevent him from referencing visual cues, leaving his instructor with the whole burden of “seeing and avoiding.”

I never liked wearing a hood when operating an airplane and if I were a GA IP I’d think long and hard about making my student wear one on departure, when you’re by definition close to other traffic and probably behind the plane. It’d probably help if more IFR flight instruction was done in simulators, but from what I’ve seen of the business, simulator use is dis-incentivized by instructor pilots, many of whom are trying to build flight time for their own Airline Transport Pilot rating.

There’s a reason we call these things “mishaps” rather than accidents because while “accidents happen,” mishaps are preventable. That’s especially true if aviators are permitted to learn the lessons from those less fortunate. Every mishap involves an element of human tragedy, and although it’s always tempting to blame an authority figure when things go wrong, the bottom line here doesn’t fit the lede – these guys died not because of the inaction of air traffic controllers, but because one of them wasn’t looking where he was going.

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Filed under Best of Neptunus Lex, by lex, Carroll "Lex" LeFon, Carroll LeFon, Flying, Lex

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