On a dark night over the Soviet Union, many years ago, a B747 on its way – in the middle of the road – from Europe to Bankok, ended up on a westbound altitude. That was a huge error. The reason was, as always, not one single mistake. Bad hearing, bad english, bad radio quality and a belief that Russian ATC controllers had the capacity to copy US counterparts, issuing clearances to altitudes assigned for opposite traffic for short periods of time. What would have been the worst aviation catastrophe thus far war averted by the healthy suspicion, from the – at the time off-duty – co-pilot of the 747, that Soviet controllers could do no such thing. After urging his colleagues to confirm the clearance, things were deemed in order. After urging them a second time, it was established that the clearance to maintain that particular level was indeed just a traffic information about another aircraft – in opposite direction – on that level, by a nice Soviet controller, having nothing to do in the middle of a very dark night. That prompted all landing lights on and climb power back to the original eastbound altitude. 4 minutes later the anti-collision lights from a THAI westbound DC-10 was spotted by the by now very alert 747 crew. The DC-10 passed underneath the 747 at the correct vertical clearance of 500 meters. It also passed underneath it, exactly enough to trigger the radio altimeter of the 747, laterally displaced less than 10 feet.
That was close. From that we can learn many things. For one thing, a mistrust for just about everything, bordering on a mental disorder, might at times prove very healthy. We can also find two of the many flaws in the aviation industry this blog is somewhat dedicated to. One is a lack of perfect communication which has in recent years been addressed and consequently can be filed among things rectified, although it took to several decades to long.
The other one is the ruling to stay on the centerline of the airway. The airway is 10 nautical miles wide, allowing for early aviators lack of precision in navigation. Todays equipment have a precision of a few feet. This implies that an aircraft on incorrect altitudes will hit another head on. Happened outside New Delhi many years ago when a Russian cargo plane hit a Saudi Arabia 747 nose to nose, killing close to 400 people. Happened recently over South America when a business jet collided with a B737, killing close to 200 people. (Fortunately some Captains break rules)
In the New Delhi case, most blame were put on the Russian crew, who ended up at the wrong altitude, having fumbled converting their more or less private meter scale to the Western World cherished feet. Here we have another flaw. Russia has since changed to feet, but one of the coming dominante aviation communities, China, still use meters to measure altitude. One would think UN could have unified the world by now, at least when it comes to altitudes for civil aviation.
The South America case presented strange findings. Air traffic controllers were blamed, pilots were blamed, faulty transponders were blamed (if they were indeed faulty, why blame the air traffic controllers). Nowhere was mentioned that close to 200 people would have come home to dinner, if right hand traffic had been introduced at the beginning of civil aviation. Anyone, be it a powerful employee in ICAO or a dynamic lobbyist, who manage once and for all to rule that all aircraft shall fly 1 mile (at least) to the right of the centerline of a 10 miles wide airway, in a similar way that ocean crossing traffic operates, just in case someone comes at the ‘wrong’ altitude, will instantly be a hero, and remembered in history. The fact that, when he does that, the only sad thing is that, had he done it thirty years ago, some 500 live would have been saved. But still, no more innocent passengers will perish by one lane traffic.
One reason for railway systems around the world to switch from one track to double tracks was eliminate one major headache – head on collisions.