Emergency crews extract one of two people after their small plane crashed last month into a transmission tower, knocking out power to the surrounding area. (Craig Hudson/for The Washington Post)
The pilot of a small plane that slammed into a Montgomery County power line tower last month was flying below minimum altitudes while approaching the Gaithersburg airport, according to a preliminary report by the National Transportation Safety Board.
The report released late Monday does not draw conclusions about the cause of the crash but sheds new light on the minutes leading up to it, detailing pilot Patrick Merkle's interactions with air traffic control and outlining flight-tracking data.
The Nov. 27 crash launched a multi-hour rescue effort to deenergize the tower and haul Merkle and his passenger from the plane, which was lodged more than 100 feet up. Power outages rippled across the region and in the dark, curious residents gathered to watch a rescue that emergency crews have called a once-in-a-lifetime mission.
Merkle said Tuesday morning that he hadn't seen the preliminary NTSB report and was due to issue his own report to investigators Wednesday.
He was flying the return leg of a trip to an airport in White Plains, N.Y., bound for the Montgomery County Airpark. As Merkle approached, visibility was severely limited and a bad-weather warning known as a SIGMET was in place for the area, according to the NTSB report. As Merkle's 45-year-old Mooney M20J got close, another plane called off an attempt to land at the little airport, according to the report.
Merkle pressed on. But as an air traffic controller directed him to a waypoint about 13 miles from the runway, Merkle made a wrong turn, according to the NTSB.
The controller provided more headings to Merkle, the report says; "however, the pilot made a series of left and right turns, near course reversals, or continued established headings as the controller repeatedly requested that the pilot turn to a different heading."
The controller spelled out the name of the waypoint, BEGKA, and Merkle said he had entered some information incorrectly and was making a fix, according to the report.
Merkle reached that waypoint about 225 feet below the minimum altitude, and then dipped even lower below the minimum altitudes for two subsequent waypoints, according to the report.
"I got down a little lower than I should have," Merkle told a 911 dispatcher after the crash.
Jeff Guzzetti, a former NTSB and Federal Aviation Administration crash investigator, said that under the conditions, Merkle should have found somewhere else to land.
"In that kind of weather at that altitude, you're just playing with fire to not follow the procedures to the letter," Guzzetti said.
The impact with the tower separated one of the propeller blades from the plane, according to the report.
Firefighters teamed up with utility crews to stage the rescue, eventually using a utility truck to reach Merkle and his passenger, Janet Williams. They were both taken the hospital. Merkle was released the day after the crash. Williams' condition was not immediately clear Tuesday.
The NTSB report notes that Merkle had described the sky as being like "pea soup" in media interviews after the crash, and that he questioned whether his altimeter was working correctly. The NTSB had the device tested, the report says, and found that it was "well within the test allowable error at all ranges."
The plane had its most recent annual inspection on Feb. 1, and Merkle received a Federal Aviation Administration medical certificate on Aug. 1, declaring that he had 1,432 hours of flight experience.
The aircraft was dislodged from the tower after Merkle and Williams were rescued, a job that required recovery crews to separate the airframe from the engine. The report describes the damage to the plane as "substantial."
A final NTSB report providing an official cause for the crash will probably not be available for months.
