According to Keith Holloway, NTSB on-scene spokesperson, “We are still in the process of gathering factual evidence at the scene. We expect the craft to be removed from the scene by the end of today.” Holloway indicated that the craft would be taken to another location for further investigation. “We have not determined the cause of the crash at this time.”

The helicopter crash on Sunday was the fourth such fatal incident in Maryland since 1972. Each previous crash killed a two-person crew in a Bell Jet Ranger.

Prior to Sunday’s crash, the most recent accident was in January of 1986. After the 1986 crash, Maryland adopted new, more stringent safety procedures and increased the standards for pilots with accompanying trauma medical personnel aboard. The moved led the state to purchase new helicopters. The helicopter crash on Sunday involved the second oldest aircraft in the fleet.

The details of the events leading up to Sunday’s crash have been stated as follows by NTSB:

Trooper 2 departed under visual flight rule conditions to rescue two highway accident victims near Waldorf, Md. The aircraft (N92 MD), call sign “Trooper 2,” departed the automobile accident site for Prince George’s County Hospital Center but diverted back to Andrews AFB—for reasons unknown to investigators.

Preliminary readouts of Potomac Tracon air traffic control tapes indicate that at 11:37 pm. local time on Sept. 27 Tracon tagged “Trooper 2” in its airspace. The 10:55 pm Andrews AFB weather indicated visibility seven miles with a broken ceiling at 1,300 feet. The 11:55 pm FAA weather report indicated visibility at 4 miles with mist, a broken ceiling at 500 feet and scattered clouds at 200 feet. At 11:48 pm, Trooper 2 requested an ILS approach for Runway 1 at Andrews. About eight minutes later, aircraft switched to Andrews tower. Controllers cleared Trooper 2 and provided vectors for the approach to Runway 19R, which was the active runway at the time.

When the aircraft was about 4 miles out on final, the pilot told controllers that he was having trouble capturing the glide slope. The tower indicated to the pilot that the glide slope equipment was operating.

When the helicopter was about 3.5 miles out, Trooper 2 requested an airport surveillance radar approach so that controllers could talk the aircraft down. The request was acknowledged when the aircraft was about 2 miles out. That was the last known transmission. The pilot made no distress call. Maryland State Police informed the NTSB that the aircraft had an emergency locator responder, but no signal had been transmitted.

The safety board has long sought safety enhancements in EMS operations. In January 2006, the NTSB issued an EMS special investigation report that covered 55 accidents involving helicopters and fixed wing aircraft. The report contained four safety recommendations.

It urged the FAA to require EMS operators to comply with operations specifications on flights with medical personnel onboard; develop and implement flight risk evaluation programs; use formalized dispatch and flight-following procedures, and to install terrain awareness and warning system.

As of this writing, the four recommendations remain open.