Maintenance Test Flight Gets A Little Out Of Control

The NTSB has just filed a preliminary report on a Hawker 125-800A maintenance test flight that got more than a little out of hand... with a stall that not only required aggressive recovery, but apparently a recovery that at some points, was conducted in IFR conditions. Read the NTSB Prelim and see if you don't get that same "Pucker"  sensation we got when reading this thing. We'd hate to have been the folks who had to clean this airplane after THIS flight...

NTSB Identification: CHI06IA127
14 CFR Part 91: General Aviation
Incident occurred Thursday, May 04, 2006 in Lincoln, NE
Aircraft: Corporate Jets Limited BAE125-800A, registration: N71MT
Injuries: 6 Minor.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On May 4, 2006, about 1800 central daylight time, a Corporate Jets Limited BAE 125-800A (file photo, below), N71MT, owned and operated by Raytheon Aircraft Company on a maintenance test flight, lost control while setting up for a stall series at 17,000 feet mean sea level (msl) near Lincoln, Nebraska. The flight was being conducted under 14 CFR Part 91 on an instrument flight rules (IFR) flight plan. Visual meteorological conditions prevailed at altitude and during landing. Instrument meteorological conditions were encountered during the uncontrolled descent prior to recovery. The 2 pilots and 4 passengers sustained minor injuries. The local flight departed LNK at 1729 and landed at 1816.

The pilot reported that the flight was entering a stall series in accordance with the test flight procedures. Flight crew calculations indicated that the stick shaker was expected to activate at 115 knots, with stick pusher activation at 107.5 knots. Aerodynamic stall was expected at 105.5 knots at the current operating weight. The pilot stated that "as the airplane slowed through [approximately] 126 knots [indicated airspeed], it abruptly rolled off / dropped the right wing and the nose fell rapidly." He noted that, although the autopilot was on as required by the test procedure, he was holding the control wheel and felt "no vibration or abnormal indication" prior to the event. He reported that the airplane rolled 5 to 7 times, both to the right and the left.

The pilot reported that the airplane entered an underlying cloud layer approximately 12,000 feet msl. The airplane exited the cloud layer about 10,000 feet msl and was "descending vertically," according to the pilot. He stated, "I neutralized the ailerons with the yoke and began a higher than normal back pressure pull-out, experiencing [approximately] 4 - 5 Gs. The aircraft responded, and we stopped the descent somewhere below 7,000 [feet msl]." The flight subsequently returned to LNK and the crew executed an no-flap landing without further incident.

FMI: www.ntsb.gov, www.raytheon.com