Preventing Another Hudson Midair

Although the people at Fox News have always been very nice to me when they call and ask for my technical expertise on aviation matters, I must admit I do sometimes dread their calls. That’s because their phone calls usually means something bad has happened, as it did when they rang me last weekend about 10 minutes after the helicopter and the the Piper PA-32 ran together over the Hudson River. Nine people lost their lives. The amateur video of the crash made the point that pilots simply looking out the window to avoid other aircraft doesn’t always work.

No surprise too when plenty of people began pointing fingers of blame at, the helicopter pilot, the Cherokee pilot, the air traffic controllers at Teterboro Tower – who were yesterday suspended in fact – and this somewhat unregulated look to air traffic in the New York area. And let’s not forget that folks in the New York area are highly-sensitized to things flying over their heads, and with good reason too.

Perhaps it won’t be this accident alone that causes a change, but eventually more intense air traffic demands will force the industry’s hand.  I also gave a radio interview about the future of collision avoidance to WRHU in New York on Tuesday. My friend Max Trescott and I were also talking last night how the accident could have been prevented and came to very much the same conclusion. A traffic avoidance system based upon transponders – transponders are already required in this airspace – might very well have prevented this tragedy. The business jets I fly – as well as all airliners – are required to carry such gear. Small aircraft are not, at least not yet.

The picture above (courtesy of Garmin) shows you the kind of screen I also see in the Cirrus SR-22 that comes equipped with a basic mode of traffic avoidance software. Of course, every aircraft is not a glass panel like this, but there are less complicated versions of traffic avoidance equipment available as a retrofit in all aircraft.

How Traffic Avoidance Systems Work

Essentially, a good TCAS system searches for other aircraft with air traffic control transponders. That equipment already tells controllers on the ground about the direction and aircraft is moving, as well as its altitude. TCAS systems simply analyze this information in a way that’s more useful to pilots in the air, especially those who might NOT be in contact with ATC.

If that had been me in the airplane last Saturday with the helicopter closing from my blind spot, the traffic avoidance system would have started warning me 30 seconds before impact to tell me there was something about to happen that I might yet prevent. It would have sounded like this to the pilot. If both the helicopter AND the Piper were so equipped, both pilots would have received the alert.

In this photo, the big yellow circle on the Primary Flight Display above would be the visual representation of the approaching intruder. A tag attached to the yellow dot also tells me the altitude of the intruder reference my aircraft … – 200 means the aircraft is currently 200 feet beneath my altitude. Plenty close for sure, but not dead on. If the altitude read showed “00” that tells both pilots the other aircraft is at exactly the same altitude and that a midair is imminent. The traffic dots give any pilot a chance to take action, such as turn away. As the traffic conflict gets closer to a collision point, the yellow dots will turn red and repeat the traffic alert.

Larger aircraft also include an added element of sophistication called resolution alert. On board an airliner or a business airplane, the computer will give the pilot the best route to take to avoid a collision, a particularly helpful tool when time is short. In this case, the aircraft is being told to change altitudes and it sounds like this.

Although all large aircraft carry traffic avoidance equipment, it is not yet required on small aircraft. My guess is that in the New York area, and other larger metropolitan centers this will soon become required … and it should.