When visibility is good, pilots of regional airline jets bound for Reagan National Airport expect to hear a familiar request from air traffic control as they fly north up the Potomac River: Can the flight crew divert to Runway 33?
Pilots who agree initiate a swooping turn that on final approach brings them northwest and low across the river - the path American Eagle Flight 5342 was on last week when it and a U.S. Army helicopter collided.
While the primary approaches to the airport’s main runway provide jets with hundreds of feet of clearance over the busy helicopter corridors that run along the Potomac, there is no such cushion for Runway 33.
The charted approach for that alternative landing takes jets within 15 feet of the top of the Route 4 helicopter corridor as it is depicted in navigation maps, according to a Washington Post analysis of Federal Aviation Administration documentation.
With little margin for error, the design places intense responsibility on air traffic controllers and helicopter pilots to stay clear of jets navigating a low and highly technical approach to the airport’s shortest landing strip, experts said. Several airplane pilots interviewed by The Post described close encounters with helicopters while approaching Runway 33, and other pilots have filed reports about such incidents to a federal aviation safety database.
The helicopter route and landing path for the runway essentially put aircraft “in the same place,” said Scott Dunham, who has worked as a National Transportation Safety Board investigator and an air traffic control instructor. “You have to move one of them.”
When necessary, current and former air traffic controllers said, the tower will alert helicopter pilots to the presence of an approaching jet - as it did last Wednesday when the Army helicopter neared the path of Flight 5342 - and ask if they can see it. If they can, controllers ask the pilot to maintain “visual separation,” meaning they will keep the plane in sight and use their own discretion to avoid a collision. Helicopter pilots who cannot see a jet on final approach are asked to hold at points north or south of the crossing, they said.
Still, aviation experts who reviewed The Post’s findings said they were surprised the FAA had designed the airline and helicopter routes in such close proximity. Runway 33 for decades was used by prop planes and private aviation. As airlines have increasingly relied on small regional jets, those aircraft have been asked to land on Runway 33 to help ease congestion at the busy airport.
John Cox, a retired airline captain who specializes in collision investigations, said the arrangement creates risks. “There’s too much of a chance of altimeter error, a gust of wind, a non-optimally flown approach where you’re a little low,” he said. “You want margins. Even 100 feet is pretty close.”
That’s especially true because, according to navigation documents, pilots control their planes manually on the final approach to Runway 33, meaning the path of their descent will vary from the FAA-designated approach.
The National Transportation Safety Board has not said precisely where or at what altitude last week’s crash occurred. In the moments before the collision, the Army Black Hawk had been flying above the 200-foot ceiling for helicopters in the area, The Post has previously reported. The cause of the collision, which left 67 dead, remains under investigation.
[Remains of all 67 victims of the deadly midair collision near D.C. have been recovered]
Ken Biddulph, a retired Army Black Hawk helicopter pilot who was previously assigned to the aviation unit involved in last week’s crash, said that because helicopters must descend to such a low altitude to avoid planes near the airport, he used to visualize the route as “flying a tunnel through their airspace.”
Of the possible vertical separation between planes and helicopters where the two routes cross, he said, “It’s just one of the closer ones in the nation that I can think of.”
Asked late last week about the proximity of the two published routes, an FAA spokesman declined to comment, citing the crash investigation. “The FAA will quickly take any actions necessary based on evidence from the investigation,” the agency said in a statement.
The National Air Traffic Controllers Association also declined to comment.
Transportation Secretary Sean P. Duffy said Friday that the government had closed helicopter Route 4 to certain aircraft, at least through the initial stage of the investigation, saying the decision would “immediately help secure the airspace near National Airport, ensuring the safety of airplane and helicopter traffic.” The corridor can still be used by helicopter flights related to lifesaving medical support, active law enforcement, active air defense or presidential transport, the Transportation Department said.
Over the years, helicopters have flown directly under low-flying planes at this midair intersection, in some cases causing the larger aircraft to pull up to avoid a possible collision, according to records and interviews.
“It can get really sketchy,” said Richard Gallaher, a helicopter pilot who for years flew corporate executives in and out of downtown Washington. Gallaher said that more than once during the 1980s and 1990s, he spotted a jet on final approach as he neared the intersection and dropped his altitude to under 100 feet to safely pass under a plane that was simultaneously coming into Runway 33.
“I’ve flown underneath and looked up into the wheel well,” he said.
Airline pilots, meanwhile, told The Post they have looked down in surprise to see a helicopter passing below, an experience they said is not common on final approach at other airports.
One regional jet pilot, who spoke on the condition of anonymity because he still flies for a major airline, said he was shocked the first time a helicopter flew under him as he was making the final approach to Runway 33. He described how the air traffic control tower told him the chopper would maintain visual separation, but the helicopter never slowed down, prompting him to pull up as the helicopter shot past. His evasive maneuver, he said, left him on a steeper and more dangerous descent to the short runway. The pilot said the experience left him shocked and furious.
“I realized that they will let those helicopters do anything once they say ‘traffic in sight,’” he said, describing the practice as “totally insane.”
The FAA’s published protocols for flying in the D.C. area set forth standards that allow aircraft to be in closer proximity than would be permitted in much of the country. Most flying is conducted under what are known as “visual flight rules,” and pilots are instructed to maintain one of the following: 1½ miles of lateral separation, 500 feet of vertical separation or “visual separation.”
FAA guidelines do not specify what distance is allowable under visual separation but say none of those instructions should be “interpreted as relieving pilots of their responsibilities to see and avoid other traffic.”
The largest planes departing and arriving at National use its longest landing strip, designated as Runway 1 or 19 depending on whether traffic is coming from the north or south. At close to 7,000 feet long, it is the airport’s only runway able to accommodate many larger commercial jets. It is the nation’s busiest runway, with an average of more than 800 takeoffs and landings combined each day in 2023, the airport says.
Pilots of smaller regional jets told The Post that, when approaching from the south, they are regularly asked to reroute to Runway 33 to relieve pressure on Runway 1 - as American Eagle Flight 5342 was on Wednesday night.
The request to divert to the roughly 5,200-foot runway typically comes from air traffic control as a plane flying up the Potomac River nears the Woodrow Wilson Bridge, they said. All jets approaching the main runway pass over Route 4 near the bridge, at least 700 feet above the maximum altitude allowed there for helicopters, The Post found.
To line up for the Runway 33 approach, pilots turn their jets eastward, the start of an arc that takes them away from the Potomac and over the District. Then, spotting a radar dome at Joint Base Anacostia-Bolling or the steeple of a white church - two landmarks designated by airlines as visual cues to begin final descent - the pilots turn northwest back toward Virginia. The path brings jets back over the Potomac River and over helicopter Route 4.
The FAA does not give precise coordinates for the edges of the corridor that helicopter pilots can use to fly north and south along the river. Pilots, who fly manually in the area, told The Post they try to adhere to the path depicted on the FAA navigational chart. The Post analysis used the edges as drawn in that chart.
Helicopters that hug the east side of the river, the D.C. side, are farthest below the approach path. The closer a helicopter is to the center of the river, the less vertical space there is between it and the path of a descending plane.
On the final approach to Runway 33, a plane on the path prescribed by the FAA reaches the airspace over the depicted helicopter route at an altitude of just under 250 feet, and exits it at just under 215 feet, The Post’s analysis found.
Pilots have documented close calls with helicopters at that spot in the Aviation Safety Reporting System. The database does not include the names of airlines or pilots involved, nor does it indicate whether the incidents were ultimately investigated or verified by federal authorities.
In 2013, a commercial jet pilot reported that a helicopter turned into the plane’s path after initially acknowledging visual separation. The captain, who was in the final approach to Runway 33, “made a hard right turn and executed a missed approach to avoid a collision,” the pilot wrote in the report.
A regional jet pilot in 2015 described a close call with a helicopter while coming into the final approach, despite having followed the airline’s approach guidance “exactly as planned.” The plane had to be steered onto a new course “to prevent it from becoming a midair collision,” the pilot wrote, noting that only later did the tower inform the plane of the helicopter’s location, by which point “it would have been too late.”
“Maybe they don’t have a specific guideline to keep the arriving traffic separated from the low flying helicopters,” the pilot wrote.
Last Wednesday night, an air traffic controller alerted the Army Black Hawk helicopter to the presence of Flight 5342 two minutes before the aircraft collided, and again just seconds before, audio recordings show. The controller also instructed the helicopter to go behind the path of the airliner.
Dunham, the NTSB investigator, said the controller seemed to have taken appropriate action. He said that in light of the crash, aviation officials may have to examine whether to keep Route 4 intact while allowing landings on Runway 33.
“You could decide this one isn’t worth it,” he said.
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Ian Duncan, Alice Crites and Aaron Schaffer contributed to this report.
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Methodology
For this story, The Post mapped the approach to Runway 33 along with the helicopter corridor known as Route 4 to determine where the two paths cross.
The FAA’s charts of helicopter routes specify maximum altitudes at various points, but they do not give precise coordinates for the edges of the corridors. By overlaying the Federal Aviation Administration’s geo-referenced navigation chart onto Google Earth Pro, The Post approximated the width of Route 4 as depicted on the chart.
The Post used the FAA’s published route for instrument-guided landing on Runway 33 to calculate the slope and altitude at which planes descend across the Potomac River toward Reagan National Airport.
Through a linear analysis, The Post determined the altitude at which a plane would cross over the eastern and western edges of Route 4.
The Post used the same techniques to examine the vertical separation between helicopter routes and three other common approaches to runways at the airport.