(The Hill) — A growing number of House lawmakers are calling for a congressional investigation into the inter-agency communication debacle that led to the emergency evacuation of the U.S. Capitol complex on Wednesday evening.

The lawmakers are stunned that an Army paratrooper stunt at the Washington Nationals baseball stadium — a pre-planned event that allowed a small, twin-engine plane to enter highly restricted airspace near Capitol Hill — could trigger so much chaos even as Washington law enforcement agencies are under heavy pressure to improve security protocols following the deadly attack on the Capitol last year.

While the Federal Aviation Administration (FAA) was aware that the Army aircraft would be circling Nationals Park, roughly a mile south of the Capitol, the agency did not inform the U.S. Capitol Police, according to the police department and lawmakers. The communication failure prompted the USCP to issue a startling evacuation order warning that the unidentified aircraft “poses a probable threat to the Capitol Complex.”

The order was quickly reversed, and the FAA says it’s investigating the mishap. But a number of lawmakers think a congressional probe is also merited.

“I think, certainly, we’ve got to get to the bottom of what happened,” House Majority Leader Steny Hoyer (D-Md.) said Thursday by phone.

“It’s amazing … that not everybody was fully notified,” he added. “It’s hard to imagine.”

Rep. Jason Crow (D-Colo.), a former Army Ranger who served in both the Iraq and Afghanistan wars, was not on Capitol Hill during Wednesday’s evacuation. But he said it affected his staff, and was particularly traumatizing for those who had experienced the Jan. 6, 2021, attack on the Capitol by a pro-Trump mob.

“It’s triggering for so many folks that were here on that day,” he said. “So we have to look into it, we have to figure out what went wrong, and there has to be some accountability, because clearly the ball was dropped.”

The small plane carrying the Army’s paratrooper unit, known as the Golden Knights, had taken off Wednesday evening from Joint Base Andrews, a massive facility just outside Washington’s Beltway in Maryland, and headed to Nationals Park to participate in Military Appreciation Night. The Capitol Police said that while they routinely receive notice of “hundreds of authorized flights in the restricted airspace” each week, the plane ferrying the Golden Knights was not among them.

“The decision to evacuate the campus is not one we take lightly,” the department said Thursday in a statement. “It is extremely unusual not to be made aware of a flight in advance.”

The Capitol Police issued their evacuation order just after 6:30 p.m., and rescinded it less than 20 minutes later, after determining there was no threat.

The scare was short-lived, but forced countless numbers of Capitol Hill staffers to flee the complex. And it infuriated Speaker Nancy Pelosi (D-Calif.), who wasted no time issuing a statement condemning the incident as “outrageous and inexcusable.”

“The unnecessary panic caused by this apparent negligence was particularly harmful for members, staff and institutional workers still grappling with the trauma of the attack on their workplace on January 6th,” she said.

The U.S. Army Recruiting Command issued a statement on Thursday saying the Golden Knights had followed all the proper protocols for flying into restricted airspace around the Capitol.

“We have confirmed that the parachute team filed all appropriate and required Federal Aviation Administration documentation and received FAA approval prior to operating within the National Capitol Region’s airspace,” said spokesperson Kelli LeGaspi.

In a statement of its own, the FAA appeared to acknowledge that the error originated in its offices.

“We know our actions affect others, especially in our nation’s capital region, and we must communicate early and often with our law enforcement partners,” the agency said, vowing “a thorough and expeditious review” of Wednesday’s events.

Whether a congressional investigation will follow the agency’s probe remains unclear. A Pelosi aide said the FAA’s internal review is the “first step.” And Rep. Rick Larsen (D-Wash.), the chairman of the Transportation Committee’s sub-panel on aviation, said that while he’s directed committee staff to seek information from the FAA, he has yet to hear directly from the agency.

“I expect to see the results of the agency’s investigation soon,” Larsen said in an email.

While such incidents are highly uncommon, it’s not the first time the Capitol has been evacuated over the false threat of an attack by aircraft. In 2004, Pentagon officials were close to scrambling fighter jets to shoot down an unidentified plane flying over restricted airspace in Washington. The twin-engine aircraft was carrying the governor of Kentucky, Ernie Fletcher (R), to Ronald Reagan’s funeral.  

Hoyer, who was in the Capitol Rotunda when that evacuation order came down, said it “caused a real panic.”

“Ultimately it was resolved before everybody exited the Capitol. But it was an incident that caused a lot of disruption,” he said. “You would think that the folks who were running this effort would know that everybody needs a heads-up if you have a small airplane flying anywhere close to the Capitol dome.”

In another strange incident in 2015, a Florida postman protesting campaign finance laws piloted a gyrocopter across the National Mall and landed it on the Capitol grounds. He was arrested without incident and sentenced to four months in prison.

Rep. Marcy Kaptur (D-Ohio), who said she landed in Washington Wednesday night just after the Capitol evacuation had ended, praised the Capitol Police officers who directed the process.  

“The officers did their job, they were worn out by the time I got there,” she said.

She was quick to add that the incident also made clear that communication between the nation’s security agencies needs to improve.

“We’d better establish a rigorous chain of accountably,” Kaptur said. “I think that’s what it taught us.”