A military aircraft is seen from the baseball stadium Nationals Park during a performance by the parachute team the Golden Knights, in Washington, U.S., April 20, 2022, in this picture obtained from social media. @dcgrasstracker/via REUTERS
A military aircraft is seen from the baseball stadium Nationals Park during a performance by the parachute team the Golden Knights, in Washington, U.S., April 20, 2022, in this picture obtained from social media. @dcgrasstracker/via REUTERS Reuters / @dcgrasstracker

The U.S. Federal Aviation Administration (FAA) told Congress it has taken "immediate action" to ensure U.S. Capitol Police are aware of unusual aerial events after an April 20 small airplane flight that prompted a security scare.

FAA Acting Administrator Billy Nolen said in a letter to Congress that the agency will provide advance notification of special event flights in the Washington-area.

Nolen said the agency believes "this will provide all of our interagency partners with the extra time necessary to reduce any potential confusion," the letter dated Friday said. "The steps we have taken will provide an additional margin of safety by reducing confusion on any unusual flight operation."

A single-engine DHC-6 plane flying the U.S. Army's Golden Knights parachute demonstration team over a nearby Washington Nationals baseball game last month was mistaken for a potential security threat and prompted an evacuation of the U.S. Capitol.

The FAA, which publicly apologized last month, declined to comment Wednesday.

The FAA submitted a seven-page event timeline, which confirms the FAA's Air Traffic Security Coordination team at the National Capital Region Coordination Center (NCRCC) "did not provide this advance notification" as was commonly done before similar flights.

The timeline says a Capitol Police watch officer at the NCRCC advised a U.S. Capitol police officer that the plane spotted was an authorized flight.

A separate FAA document confirmed the plane did not enter prohibited airspace around the U.S. Capitol.

Nolen also said he had met earlier this month with Capitol Police Chief J. Thomas Manger. Capitol Police did not immediately comment.

U.S. House of Representatives Speaker Nancy Pelosi last month criticized the "outrageous and frightening mistake."

Her office referred questions Wednesday to her prior statement.

The U.S. Capitol Police initially said they were tracking an aircraft that posed a "probable threat" but minutes later said there was no threat.

Pelosi said last month Congress wanted to know who at the FAA "will be held accountable."