Learning Experiences

It was warm and cozy in the cockpit. The pilot and his family were southwest-bound, en route to a summer vacation in the mountains. The weather was perfect and the pilot stared straight ahead, dreaming about reeling in a near-trophy-size trout. As he daydreamed, his eyes lost focus and he was vaguely conscious that he should be paying more attention to heading and altitude. But then, that's what autopilots are for, right? "Let's see, 8,500 feet. The altitude hold is right on the money."

Suddenly, out of the corner of his left eye, he noticed something moving. Instantly alert, the pilot's eyes focused and his heart leaped. By the time he turned his head there was only time to register the startled faces in the northwest-bound Cessna 310 before it disappeared under him. Twisting to look out the other window, he saw the Cessna shoot from just behind the right wing and speed away.

"That was close! Stupid pilot - what's he trying to do? Kill somebody?" The pilot became more agitated as he realized just how close he'd been to a midair collision. "He was at my altitude! If I had gotten his N-number I'd report him to the FAA. Pilots like that shouldn't be flying!"

The pilot was understandably shaken. He was angry at the other pilot, on whom he placed the blame for the incident - but was he being fair?

The vacation-bound pilot was flying southwest at 8,500 feet. His altitude was in accordance with Federal Aviation Regulation 91.159, which says a pilot flying VFR in level cruise at more than 3,000 feet above the ground shall fly at an even thousand-foot altitude plus 500 feet when on a magnetic course between 180 to 359 degrees. The Cessna 310 pilot was cruising northwest, so his even thousand altitude plus 500 feet was in accordance with FAR 91.159, too.

The FARs provide basic collision avoidance rules. You could reduce the potential for converging aircraft to be flying at the same legal altitude by establishing separate cruising altitudes for each 90 degrees of direction, rather than 180 degrees, but that would cut our choice of cruising altitudes in half. (For example, flying northeast you could only cruise at 3,500, 7,500, 11,500, etc.) The problem with 91.159 not only is converging aircraft, but aircraft flying at near-head-on courses. When one pilot flying a course of 358 degrees meets another pilot at the same altitude on a course of 182 degrees, both pilots are flying at a legal altitude - even though they are, for all practical purposes, approaching each other head-on.

FAR 91.113 addresses converging aircraft, and it says the aircraft on the right has the right of way. This being the case, the vacation-bound pilot had the right of way. If the 310 pilot hadn't seen the other aircraft at the last moment and avoided the collision, this would have been a great point for the lawyers to argue - but it would have been a moot point for the people in the two airplanes.

In 28 years of flying, I've never seen or heard of a pilot deliberately buzzing or otherwise placing his aircraft in unsafe proximity to another aircraft. But I have survived two airplanes getting uncomfortably close before either pilot saw the other. I strongly suspect I was involved in other similar incidents I was never aware of. When you don't see another aircraft, you don't see it.

Sometimes you will not see the other aircraft. Under the right combinations of light, visibility, aircraft coloration, and background, any aircraft can be nearly invisible. You have no guarantee that even the most careful pilot with the most disciplined scan will see another airplane under these conditions.

The only solution is to support an active traffic scan with good preflight planning. If you fly on an airway, examine your sectional charts for crossing airways and know at what altitudes possible crossing traffic might be flying. Be especially vigilant when crossing over a navigation aid such as a VOR. Remember, you might not be the only pilot flying to that station. When you fly near the boundaries of Class B and C airspace, be aware of the traffic descending into or climbing out of this airspace. At many of these airports, the airplanes follow predetermined routes, which are shown on sectional and terminal area charts. Remember, as you scan for traffic, don't just scan your altitude, look above and below it as well. Pilots flying on instrument flight plans can be the worst complainers when another aircraft gets too close to them. Because they are wrapped in ATC's blanket of radar separation, some of them believe their IFR clearance gives them ownership of the airspace along their route and altitude. But IFR pilots forget sometimes that - when they are not in the clouds - they must see and avoid just like any VFR pilot.

Also, IFR pilots must remember that when ATC sees a conflict with a VFR target, the controller has no legal obligation to attempt to separate the two, but the controller will advise the IFR pilot of the traffic, and will advise the VFR pilot, if he's receiving flight following.

It's a different story inside Class B and C airspace, where all pilots are talking to ATC. If the controller sees a conflict, he will vector aircraft on headings to resolve the conflict. This does not, however, remove the pilots responsibility to see and avoid other aircraft in visual conditions.

Pilots would do well to remember that controllers are human. Sometimes a potential conflict is clearly developing on the radar scope and the controller just doesn't see it. There's no use blaming the controller if an incident occurs in visual conditions. Diligence in watching for VFR aircraft is part of the IFR pilot's job. The controller merely assists the pilot in discharging that responsibility.

You have no guarantee you'll never have a close call as the result from an altitude conflict, but you can guard against it. Fly at the correct cruising altitude as defined by FAR 91.159. When on a magnetic course of 360 to 179 degrees, fly at any odd thousand-foot altitude plus 500 feet. When on a magnetic course of 180 to 359 degrees, fly at any even thousand-foot altitude plus 500 feet. (Note that the rule says "magnetic course," not "heading." If you're following a magnetic course of 182 degrees but an easterly wind causes you to fly a heading of 172 degrees to stay on course, you should be flying at an even thousand-foot altitude.)

Then fly that altitude because IFR cruising altitudes follow the same odd and even thousand-foot rule without the additional 500 feet. Finally, make sure you use the current altimeter setting.

As our vacation-bound pilot learned, being at the correct cruising altitude doesn't mean you can't run into another airplane. When you fly your mind should be on one thing, and one thing only - flying the airplane. In other words - scan, scan, scan, and scan again for traffic regardless what airspace you're flying in. To help other pilots see you, turn on your airplane's lights - even during the day. Ask your passengers to scan for traffic, too. If you're flying with kids, make it a game, with perhaps a treat for every airplane they see before you do. You'd be surprised how good those young eyes are once the children are motivated.

There really is no absolute way to avoid the possibility of a midair collision because of an altitude conflict. Even high-flying aircraft such as the SR-71 or U-2 have to climb and descend from their lofty heights, which puts them in potential conflict with other traffic. Because we have only so many altitudes we can use, more than one pilot may use them at one time, which means all pilots need to share them safely.