Midair Collision at DCA

Updated February 3, 2025

The collision between a PSA Airlines Bombardier CRJ-700 regional jet and an Army UH-60 Black Hawk helicopter at Washington Reagan National Airport (DCA) on January 29, 2025, is a tragic event that will demand a thorough investigation. Midair collisions in controlled airspace are rare, but when they do occur, they often expose breakdowns in situational awareness, communication, and traffic management. Given the complexity of DCA's airspace, the mix of civilian and military operations, and the challenges of nighttime flying, the pieces of this incident are starting to form a picture—one of human error, procedural vulnerabilities, and possibly a failure of collision avoidance systems to intervene in time.

Piecing Together What Happened

American Airlines Flight 5432, a CRJ-700 operated by PSA Airlines, was on short final for Runway 33, descending through 400 feet—just seconds from touchdown. At the same time, an Army UH-60 Black Hawk, call sign PAT25, was flying perpendicular to the jet's flight path along the Potomac River. The river serves as a designated helicopter flight corridor, often used by military, law enforcement, and emergency services.

There was a critical distinction in how these two aircraft were operating. Flight 5432 was under Instrument Flight Rules (IFR), meaning it had priority and was under direct air traffic control guidance. PAT25 was operating under Visual Flight Rules (VFR), meaning the helicopter crew was responsible for visually maintaining separation from other aircraft.

As the CRJ-700 made its final descent, DCA Tower called PAT25 and asked them to confirm they had the "other aircraft in sight." The response from PAT25 was clear: "We have the aircraft in sight." But a second later, the collision occurred. Having watched multiple videos and listened to the audio of the radio communication between the tower and the two involved aircraft, it now seems clear that the helicopter was looking at the wrong traffic, possibly identifying a different plane—perhaps a departing jet climbing out of DCA—and mistakenly believed they were clear of conflict. Misidentification of traffic is not uncommon in busy airspace, particularly at night when depth perception and distance estimation are more challenging. Adding to this challenge was the light saturation from the dense city below.

Could TCAS Have Prevented the Collision?

One of the first technical questions investigators will examine is whether TCAS (Traffic Collision Avoidance System) was functioning and whether the CRJ-700 crew received any alerts before impact. TCAS is designed to detect potential midair conflicts and provide pilots with automated advisories to either climb or descend.

Onboard commercial jets, TCAS II issues two types of alerts:

    Traffic Advisory (TA): A warning that another aircraft is close.

    Resolution Advisory (RA): A specific command to climb or descend to avoid a collision.

One of the weaknesses of TCAS is that it relies solely on vertical maneuvering, which isn’t always feasible in a low-altitude landing scenario. During descent, TCAS on an airliner typically stops issuing Resolution Advisories (RAs) around 1,000 feet above ground level (AGL) to avoid false alerts from ground traffic. Traffic Advisories (TAs) might still be given down to about 400 feet AGL. The system uses radar to assess ground proximity, inhibiting alerts when aircraft are clearly on the ground. It also benefits from airport databases to understand traffic context and considers the aircraft's own configuration, like gear down or flaps extended, which signals the landing phase, further tailoring alert issuance. These details can vary depending on the TCAS version and aircraft.

While all commercial airliners are required to have TCAS, military helicopters like the UH-60 Black Hawk are not necessarily equipped with compatible systems. Even if PAT25 had a form of traffic advisory equipment, it may not have been designed to interact with the CRJ-700’s TCAS.

The important questions now will be:

    Did Flight 5432 receive a TCAS alert before impact?

    If so, did the crew have time to react, given that they were only 400 feet above the ground?

    Did PAT25 have any onboard collision avoidance system at all?

Another technology to consider in this incident is Automatic Dependent Surveillance-Broadcast (ADS-B), which allows aircraft to determine their position via satellite navigation or other sensors and broadcast it to air traffic controllers and other aircraft. If PAT25 was equipped with ADS-B but not transmitting, this could have hindered the situational awareness of both the helicopter and the CRJ-700. Additionally, the Secretary of Defense has mentioned that the pilots might have been "goggled up," meaning they could have been wearing Night Vision Goggles (NVGs), which can significantly alter visual perception. NVGs allow pilots to see in low-light conditions but can also cause tunnel vision, potentially reducing the field of view and making it harder to spot other aircraft, especially in a complex environment like DCA's airspace at night.

The Impact of a Last-Minute Runway Change

Adding to the complexity of the situation was the last-minute change in runway assignment. The CRJ-700 had originally been assigned Runway 1 but was redirected to Runway 33, a shorter runway at DCA. While last-minute changes are not unusual, they introduce risks—especially at night. These may include recalculating descent profiles, adjusting navigation systems, and re-briefing the landing plan. Additionally, a new runway will place the aircraft on a different flight path than originally planned, increasing the chance of encountering unexpected cross-traffic. If PAT25 didn’t anticipate a landing aircraft on Runway 33, it may not have been scanning in the correct location for potential conflicts.

DCA’s Unique Airspace Challenges

DCA's airspace is among the most complex and highly controlled in the country. Due to its proximity to government buildings, military bases, and the White House, it is surrounded by restricted and prohibited zones.

    Prohibited and Restricted Airspace: The Washington, D.C. Flight Restricted Zone (FRZ) and Prohibited Area P-56 leave very little room for aircraft to maneuver.

    High-Density Air Traffic: Commercial airlines, corporate jets, military flights, and emergency helicopters all operate in close quarters.

    Civilian-Military Traffic Integration: Military helicopters frequently transit near DCA, but they follow different operational protocols than commercial airliners.

    Limited Missed Approach Options: Unlike many other major airports, DCA does not allow for extensive go-around procedures without aircraft encroaching into sensitive airspace.

The result is an environment where split-second decisions and absolute precision are required. Any miscommunication, misidentification, or delay in recognition can have devastating consequences.

Legal and Regulatory Implications

In the wake of this tragedy, multiple investigations will be launched by the FAA, NTSB, and possibly Congress. Some of the key areas of scrutiny will include:

    Air Traffic Control Procedures: Were proper sequencing and separation ensured?

    Military-Civilian Coordination: Did PAT25’s mission planning take into account the complexities of DCA’s airspace?

    TCAS Regulations: Should all military aircraft operating near commercial airports be required to have compatible collision avoidance systems?

    Runway Assignment Decisions: Did the last-minute runway change contribute to the accident by placing the CRJ-700 in a less predictable traffic pattern?

The FAA could face liability issues if ATC failed to ensure proper separation. If the military helicopter was improperly integrated into civilian traffic, changes in policy could be recommended.

Final Thoughts

This accident is a reminder that even in highly controlled airspace, human error and procedural weaknesses can combine to create a disaster. The apparent misidentification by PAT25, the last-minute runway change, and potential TCAS limitations all appear to have played a role.

In an airspace as complex as that of Washington, D.C., there is virtually no margin for error—this tragedy underscores the catastrophic outcomes when several system failures converge. I will conclude by noting that more information will likely emerge in the coming days and weeks. Prematurely assigning blame or drawing conclusions about the causes of this accident would be both irresponsible and counterproductive.

Addendum (February 3, 2025)

Investigations have revealed that the Army Black Hawk helicopter involved in the accident was flying above the approved altitude for its route, 200’, with preliminary data indicating it was at least 100 feet higher than allowed. On a standard 3-degree glide path, the American flight would be about 300’ on a one-mile final.

This discrepancy is still under investigation, as the data from the helicopter's waterlogged black box is being analyzed to reconcile altitude readings. The NTSB expects to release a preliminary report within about 30 days.