Scooting just above the cloud-tops in a corporate plane, veteran pilot Markus Johnson is seeking a close scrape, though not literally, with a big rock or anything else of substance jutting off the ground.
The task was much easier earlier this year, when a Tribune reporter also accompanied Johnson, the chief pilot at Honeywell, on a flight that buzzed the almost 8,000-foot-high Hurricane Ridge mountain range near the Olympic National Forest in Washington State.
But a photographer wasn’t along then to chronicle for readers the view of ever-increasing danger through the cockpit windshield as the plane flew dead-on toward lodgepole pines and jagged rock formations, then banked hard to avoid a collision–only to repeat the adrenaline-pumping thrill several times.
Johnson, whose mission in aviation is to prevent other pilots from unwittingly experiencing a decidedly much worse scenario than what we went through in a highly controlled demonstration, agreed to fly his company’s Beechcraft King Air from Paine Field in Everett, Wash., to Midway Airport in Chicago recently to replicate the exercise, albeit in the vertically challenged Midwest.
The intent wasn’t to see whether Johnson could navigate to the edge of meshing aluminum with Illinois granite, but just the opposite. Honeywell is the leading manufacturer of a flight safety tool that gives pilots–from Boeing 747 captains to students behind the stick in Cessna 172s–a keen sense of their whereabouts in the airspace.
From mountain peaks to television towers, in clear skies or zero visibility, the Enhanced Ground Proximity Warning System (EGPWS) provides notification of natural terrain and manmade obstacles in the flight path. The device, which plugs into the instrument panel and works in tandem with the aircraft’s navigation system, contains an updateable map of elevations stored in the computer’s memory. The information is based on data collected by the National Oceanic and Atmospheric Administration.
The system has saved many lives since being certified in 1996, the year an American Airlines plane with less-sophisticated technology struck a mountain peak while approaching the airport in Cali, Colombia, killing the 159 passengers and crew members aboard.
Aviation safety officials said the updated equipment might have helped Air Force pilots prevent the crash in Croatia of a plane carrying Commerce Secretary Ronald Brown that year as well as the loss of a Korean Air jumbo jet that crashed in Guam.
Since the accidents, American and other carriers have voluntarily stepped up installation of the more advanced terrain-warning equipment. The Federal Aviation Administration requires U.S.-registered airlines to have only the older version of the system, though FAA officials said new rules are being written to upgrade the standards.
The advanced system, which also contains a database of all the airports in the world, has saved pilots who lowered landing gear and set wing flaps in preparation to touch down on runways that weren’t there.
For pilots and passengers, the Honeywell product and competing versions by other manufacturers, all of which the FAA generically calls Terrain Awareness and Warning System (TAWS), represent a security blanket that works in concert with weather radar devices and collision-avoidance equipment to warn pilots of other aircraft in the vicinity.
Pilot error and a loss of situational awareness due to factors including darkness and heavy clouds contribute to planes that are airworthy and under control being flown into mountains or relatively flat ground. The phenomenon, known as Controlled Flight into Terrain, is the leading cause of aviation accidents worldwide, responsible for the crashes of almost 100 passenger planes since records were first kept in 1946.
In our King Air turboprop, flying at about 200 miles per hour, or 3 miles every minute, the pilot monitoring the terrain-avoidance system would know at a glance at least 10 minutes ahead of time whether he needs to adjust the flight path.
“If he knows the obstacle is out there, why would he even get close enough to be issued a [recorded] verbal alert?” Johnson said. “Regardless of whether you are cruising along over Kansas in beautiful weather or flying at 35,000 feet over the Himalayas at night with an engine out, you now have a virtual picture that lets you see out the window.
“And if I can always see out the window,” Johnson said, “I’m not going to run into anything, because I have this thing about staying alive.”
OK then, the reporter itching for a good story asked. “How ’bout we navigate a collision course with the Sears Tower,” which at 2,300 feet above sea level showed up as the tallest obstacle on the cockpit screen.
“No,” Johnson replied, eliciting approving nods from the Tribune photographer and Ron Crotty, a Honeywell media handler, sitting in the rear of the plane.
“Lake Point Towers?”
“Somebody will call the police or the FAA. Besides, it’s on the approach path to Meigs Field, and it’s in Midway’s airspace,” Johnson responded.
“Wrigley Field?”
“Forget it. But I would like to see a ballgame there some time,” he said.
The ski areas in southern Wisconsin were also ruled out, because the 900-foot-high bluffs and hills are too puny. We’d have to fly so low–violating FAA flight rules–that the male voice in the terrain warning system would be screaming, “Terrain! Terrain! Pull up! Pull up!” even before the plane would get close to anything.
Johnson promised to put on a good show, however. Before taking off from Midway, he studied an aeronautical chart and decided on a visit to the tip of a 1,997-foot TV tower south of Ottawa near LaSalle. The tower was about 60 miles southwest of Midway, so we would be there shortly.
The first versions of the technology, introduced in the early 1970s, essentially searched straight below an airplane to locate objects. But the first-generation models, which worked off radio altimeters, could not “see” forward, and they tended to give pilots only a few seconds of warning after detecting the ground coming up fast. The initial technology was lousy at detecting peaks and cliffs because few planes crash into the base of mountains.
Honeywell’s advanced terrain-avoidance system sweeps below and in front of the aircraft looking for obstacles. The terrain database covers elevations of at least 100 feet, whereas the minimum listed in aeronautical charts is 200 feet.
Using a plane’s global-positioning satellite (GPS) system or other navigation instruments on less sophisticated aircraft, the computer in the EGPWS unit places the aircraft in the proper 3-D point on the database map by determining its latitude, longitude and altitude. The surrounding terrain is then displayed on a color monitor.
The map-like information on the screen is easy for even a non-pilot to understand. Nearby fixed objects, natural and manmade, are shown in shades of green, yellow and red, depicting the vertical separation–or lack of it–between the plane and the obstacle.
Rings on the screen, which can be adjusted in increments of five miles, show how far away the potential threat is so pilots can gently steer clear many miles before reaching any potential threat along the flight path.
Green shadings on the monitor mean the aircraft is at least 500 feet above the obstacle; solid yellow tells the pilot the separation is less than 500 feet, and a recorded voice warns, “Caution. Terrain” if the pilot does not initiate a course change 60 seconds before reaching the area. The alert becomes more intense, and frequent, if the plane continues to head into the red zone. Thirty seconds from projected impact, the alert becomes much louder, warning, “Terrain, terrain–Pull up!”
Traveling westbound in the King Air at 2,500 feet, the TV tower appears on the screen nine miles ahead as a solid green image, signaling there is at least 500 feet of clearance. Out the window, all the passengers see is blue sky and thickening clouds under the fuselage.
The pilot points the nose down and drops 200 feet, turning the image of the obstacle on the screen yellow. The obstacle is now six miles in front of the plane as the ground proximity system’s computer continues to monitor the terrain obstacle database. The updated information appears on the screen.
“If this was a normal flight, I would be questioning air-traffic control on the radio, or turning or climbing or doing something so that I don’t continue to head right at the tower,” Johnson said. “But for the demonstration here, we’ll just kind of proceed.”
Less than three miles from the TV tower, which we still have not seen, the voice in the warning system bleats: “Caution. Obstacle. Obstacle. Obstacle. Pull up. Pull up. Pull up. Pull up … “
As Johnson pulls back on the control stick to commence a steep climb, flashing red strobe lights marking the tip of the red-and-white steel latticework of the TV tower poke eerily through the cloud-tops.
“That’s how it works,” Johnson said calmly as his passengers marveled over the close encounter, which was repeated several times.
The Honeywell unit on the King Air was the Mark V, the Enhanced Ground Proximity Warning System that is standard on all new Boeing and Airbus commercial planes. The system adds $68,000 to the price of a jetliner costing several hundred million dollars.
A $30,000 version is available for commuter aircraft and mid-size business jets. The entry model for general aviation planes runs about $9,500, which though pricey for a piston plane that may cost $70,000 or less, is considered by a growing number of amateur aviators to be a good insurance policy against calamity. Honeywell would not disclose the number of units sold.
Continuing the demonstration, Johnson offered to show how the terrain warning system can rescue a pilot who becomes disoriented or has mis-navigated and is making an approach to a runway that doesn’t exist.
Over farms west of Chicago, Johnson lowers the landing gear and descends to 1,000 feet as if he were setting up to land. The images on the screen turn yellow and the warning voice activates: “500 [feet]. Terrain. Terrain!” The command is followed moments later by urgent warnings to pull the nose up. Though the pilot is flying a standard approach, the database knows there is no runway.
For the finale, instead of making a normal straight-in or gently sloping approach to Midway, Johnson plans to navigate toward the landing edge of Runway 31 Left at a steep right angle, then at the last moment turn hard to the left and dive in for the touchdown. He receives permission from the control tower.
The runway is in sight, but neither the onboard warning system nor the digestive juices rising up one passenger’s esophagus like the unorthodox approach.
“Three hundred [feet]. Sink rate. Sink rate. Sink rate,” the warning voice announces, raising the volume of the alert with each repetition. The computer sees the runway, but it is still very unhappy that the descending plane has failed to line up properly for a landing.
“Thirty [feet]. Twenty. Ten … “
As if he were piloting a military fighter, Johnson maneuvers the plane around sharply and lands on the centerline.
“What we did was kind of on the edge of reasonable,” Johnson said. “You do that with an airplane and you deserve an alert.”
“If,” echoed the voice of the photographer from the rear of the plane, “you live to tell about it.”
Which, after all, is the point of the lifesaving system.
