In the final seconds before it careened into the houses below, pilot Michael Rosenberg fought to control a pitching, rolling airplane that was losing the ability to fly.
During the last 20 seconds of the flight, an automated warning in the cockpit chanted “stall-stall, stall-stall” in staccato rhythm.
Those preliminary findings on the crash that killed Rosenberg and two passengers as well as a mother and two young children in a house Monday were gleaned from voice and data recorders examined by the National Transportation Safety Board.
Although the plane’s twin jet engines continued to function normally, the plane slowed too dramatically to reach the runway. On final approach to landing, with flaps extended and landing gear down, the plane should have been flying at 120 mph. The cockpit data recorder downloaded in the NTSB’s Washington laboratory showed it was going 101 mph in the final seconds of flight.
“At that point, the flight data recorder started showing a large pitch and roll excursions,” said NTSB member Robert L. Sumwalt III in a news briefing Tuesday.
In keeping with NTSB regulations, Sumwalt did not speculate on what caused the crash, a conclusion that may be revealed in a final report some time next year.
He did, however, provide revealing details on the final seconds of the flight.
Near the point of impact, the Embraer EMB-500/Phenom 100 was positioned in an aerodynamic stall, with its tail sharply down and nose elevated. At that extreme angle, normal air flow that keeps a plane aloft ceases, and the plane loses the ability to continue flying.
Sumwalt said the investigation appeared to discount an early theory that birds may have caused the engines to fail, much like the famous 2009 incident when birds sucked into the jet engines of a US Airways Airbus 320 caused stalling, and the plane made a forced landing in New York’s Hudson River.
Sumwalt said the engines functioned normally until impact; there was no evidence a bird had been ingested in either of them, and pilots who were heard reporting birds in radio communications at the time later said that the birds were on the runway, not in the air.
There was no evidence that the plane had disintegrated in the air or that any portion broke away in flight. The nose, tail and both wingtips were recovered at the crash scene, Sumwalt said.
“We want to locate the four corners of the aircraft to verify that the aircraft was intact prior to the impact,” he said.
Neither did the weather — scattered clouds at 2,100 feet and a 7-mph northeast wind — appear to play a factor.
Rosenberg was a highly qualified and well-established pilot. In addition to 4,500 hours of flying time, he was certified as a commercial pilot and as a flight instructor. He also was rated to fly the Phenom, a sophisticated six-passenger jet that costs more than $4 million and is capable of speeds in excess of 400 mph.
But Monday’s crash was his second in less than five years, and the 2010 crash came as he approached the same airport — Montgomery County Airpark in Gaithersburg — while piloting a single-engine turboprop plane.
In that instance, according to an NTSB report, he approached the runway with stall warnings sounding as he touched down. The plane drifted to the left side of the 75-foot-wide runway, and Rosenberg attempted to lift off again with the intent of circling the airport for a second landing attempt.
Instead, the plane went about 100 feet to the left and crashed into trees. He escaped with a minor injury. The NTSB concluded that the cause was pilot error.
When a pilot is involved in an accident, the Federal Aviation Administration reviews the circumstances to determine whether action is warranted. Pilots who blatantly violate FAA rules could face revocation of their licences.
“If circumstances raise a question about a pilot’s skill or competence, they can send a letter and an [FAA] inspector will take them on a check ride,” said a former federal aviation accident investigator who asked not to be identified because he was not familiar with all the circumstances of Rosenberg’s 2010 crash.
The FAA did not respond to a request Tuesday for Rosenberg’s pilot history.
Rosenberg, 66, died after a 57-minute flight from Chapel Hill, N.C., near the Durham headquarters for his medical research firm, Health Decisions. Two colleagues aboard the plane — David Hartman, 52, and Chijioke Ogbuka, 31 — also were killed. Hartman was the vice president of Nuventra, a North Carolina pharmaceutical consulting firm.
“We are deeply saddened by the loss of David and will miss him both personally and professionally,” Nuventra chief executive Geoffrey Banks said in a statement. “On behalf of all of us at Nuventra, our thoughts and prayers are with David’s family as well as others affected by this terrible tragedy.”
There were three victims in the house set afire by the crash: Marie Gemmell, 36, and two of her children — 3-year-old Cole and 7-week-old Devin.