If you’ve never worked with radar, you can’t fully appreciate the contribution oil companies in the Gulf of Mexico are making to the safety of air transportation….
…Unless, of course, you encounter an Oil & Gas Journal editor who spent 4 years in the US Air Force several decades ago as a “weapons controller.”
A weapons controller is—or was, if they no longer have them—like an air traffic controller with an important difference.
Air traffic controllers use intermittent positional information provided by radar about airborne objects to tell pilots where and how fast to fly in order to keep aircraft safely distant from one another.
Weapons controllers use the information to tell pilots how to get close enough to other aircraft to blast them out of the sky.
Either species of controller can tell you a couple of things you need to know about radar if you’re to know what Gulf of Mexico producers are doing for air safety.
Rotating rectangles
Anyone who has visited an airport has seen a radar antenna. It’s a curved rectangle that rotates atop a tower.
Most radars that track aircraft are—or were 30-some years ago—pulse systems. The antenna emits a radio pulse and listens for reflection signals from objects out in the wild blue yonder. Emission of the pulse and detection of the return signal have to occur in the same sweep of the antenna.
Since the good old days, of course, improvements in computers, airborne transponders, and who knows what else have enhanced the abilities of pulse radars and ancillary systems to track aircraft.
As long as radar antennae rotate close to the ground, however, important limitations apply. Basically, maximum range becomes a trade-off with the antenna rotation rate and, therefore, sampling frequency. And an antenna positioned a few tens of feet from the ground inevitably “paints,” as they used to say, nearby buildings, utility poles, hills, birds, and whatnot, creating a presentation mess known as “ground clutter.”
While this explanation is very basic and probably dated in places, it should illuminate the gains to be had from elevating radar antennae—or something better—to altitudes well above ground level—perhaps into space.
That’s what the Gulf of Mexico oil and gas industry is helping to accomplish.
A partnership of 44 companies, the Helicopter Association International (HAI), and Federal Aviation Administration is implementing for gulf chopper transport a system destined for use by all commercial aviation called Automatic Dependent Surveillance Broadcast, or ADS-B.
Instead of ground-based radars, ADS-B uses signals from Global Positioning System satellites to monitor air traffic.
In the gulf, that’s a lot of aircraft.
According to Ann Carroll, HAI vice-president of legislative affairs, 650 helicopters serving oil and gas installations make as many as 7,500 trips/day in the 500-mile-by-250-mile aerial region off Texas, Louisiana, and Mississippi. They carry an estimated 2.6 million passengers/year.
Until now, pilots of those aircraft haven’t received the communications, weather reporting, and surveillance services that FAA provides other domestic air traffic.
When the necessary equipment is installed offshore and aboard aircraft, ADS-B will provide positional and other information—such as heading, altitude, speed, aircraft category, call sign, and distance—simultaneously to all pilots in the gulf and to controllers in Houston. Prime among the many consequent advantages will be improved safety.
To help make this possible, gulf operators are providing space on platforms and other installations for communications, weather, and other equipment and helping pay for the work. Carroll says the value of in-kind services offered by companies in the gulf to support the new system will exceed $100 million over 20 years.
Equipment related to the new aviation system becomes operational as it’s installed. The partnership’s first offshore communications site to start up was on BP’s deepwater Atlantis platform last Dec. 18.
Improving safety
Carroll expects ADS-B transformation of Gulf of Mexico airspace to be complete in December. The oil and gas industry then will have contributed to a crucial piece of what FAA calls the Next-Generation Air Transportation System, implementation of which received approval in 2005 and is expected to take 20 years.
The space-based perspective and other improvements over terrestrial radar systems will, without doubt, enormously boost the safety and capacity of US air transport.
If aviation officials ever need to get airplanes within fighting distance of one another the old-fashioned way, though, they know whom to call.
