Runway Excursion on Take-Off
This accident happened some time ago but it is new to me. A twin-engine business jet departing from Portland, Oregon, crashed shortly after take-off with four on board.
The Aerospatiale SN-601 Corvette was developed and manufactured in the 1970s as a response to a government need for a compact twin turbofan engine. Only 40 Corvettes (including the prototypes) were ever constructed before the project was abandoned after cost overruns and lack of sales: Aerospatiale hoped to sell six business jets a month but they only actually received 27 orders over the two and a half years that the Corvette was in production. A French government Court of Audit described the Corvette programme as “a major commercial and financial disaster”.
Eight of the produced Corvettes are listed on Aviation Safety Network as having crashed. But most of the other incidents are somewhat more straight-forward to understand than this one.
On that day, the Corvette had 2,305 hours in service. Owned by RL Riemenschneider, the aircraft was based in Redmond, where it was operated on the company’s behalf by Redmond Flight Center. Redmond Flight Center was licensed for an on-demand air taxi service, although the Corvette wasn’t listed on their operating certificate.
The Corvette was at Portland International Airport and parked at Flightcraft Inc, a fixed base operator at Portland offering services to aircraft and crews not based there.
The Corvette requires a two-man crew and was configured for ten passenger seats.
The flight crew had filed an IFR (instrument flight rules) flightplan to Hermiston, Oregon. The weather that morning was clear with good visual conditions and the runway was dry. Portland clearance delivery cleared the aircraft to Hermiston and the Corvette was cleared to taxi from Flightcraft to runway 10L at 09:00.
The pilot-in-command, who was also the Pilot Flying, was the director of operations of the Redmond Flight Center. He held a commercial pilot certificate and a flight instrument certificate, rated for instrument flight for single- and multi-engine land aircraft. He had completed the practical test for the SN-601 type rating six months previously. He had 4,500 hours total, of which 4,400 were in command, 3,000 were multi-engine and 125 were on type. He had completed the practical test for the SN-601 type rating six months earlier.
Another pilot was in the seated in the right seat and two passengers were in the back.
After taxiing out from the parking ramp, the pilot called ATC to say that he wished to return to Flightcraft without giving a reason. ATC cleared him to do so and the aircraft turned around and returned to the Flightcraft ramp, where he shut down the aircraft.
Witnesses at Flightcraft saw the aircraft return to the ramp and shut down and open the main entry door. The pilot was in the cockpit, holding a conversation on his mobile phone. One of the aircraft occupants told the ground service personnel that the aircraft had an engine problem.
The pilot didn’t speak to anyone at Flightcraft but flight records confirmed that he phoned Redmond Flight Center at 09:10. He asked an employee to prepare N37HB for flight: a Piper PA-31T Cheyenne twin-engine turboprop owned and operated by the same company.
They remained at the Flightcraft parking area for about five minutes and then taxied back out after receiving clearance. The pilot cancelled his IFR flight plan to Hermiston and said that he was flying VFR to Redmond instead, where his company and the Corvette was based.
He didn’t give any reason for this and later simply said that something had changed. Portland ground control gave the pilot a VFR clearance to Redmond.
Witnesses at the Flightcraft ramp watched the Corvette as it entered the runway and started its take-off run.
The Corvette’s nose lifted off about halfway along the runyway and the aircraft briefly became airborne with its wings rocking. It reached about 5 or 10 feet over the ground.
One of the witnesses, who had seen the Corvette at Portland before, said that the aircraft was flying much more slowly than usual at rotation and seemed somehow quieter.
The Corvette then settled back onto the ground and began to slide, crashing into the A1 taxiway sign before coming to a halt. The loss of control of the aircraft took place at 09:18.
The pilot contacted Portland tower on the ground control frequency and explained that he’d had an engine failure. He said that as the aircraft reached V1 he had just lifted off when the right engine failed and the aircraft yawed. He put the aircraft back down and tried to get control but the yaw caused him to run off the runway surface. He tried to keep the aircraft as straight as possible as he applied the brakes. He remembered seeing a generator light come on as he started to rotate and believed that the right engine failed at that time. Everything else was a blur.
Later he told the NTSB that everything seemed fine until he pulled back on the wheel at rotation speed. The next thing he remembered, they were sitting on the grass. He said he wasn’t actually sure what had happened.
Both pilots in the front of the aircraft submitted their logbooks to the NTSB. The two passengers in the cabin declined to be interviewed.
Runway 10L had a 10-20 foot long skid mark about halfway down which led to where the aircraft left the runway to the right. The A1 taxiway had a series of scuff marks and taxiway light debris leading up to the taxiway sign at the junction of the junction of taxiway A and taxiway A1. The sign was completely demolished. The Corvette was resting on its belly about half a mile from the initial skid mark. It was largely undamaged except for the scraped belly, fuel tanks and the leading edge of the right wing.
The landing gear and flaps were both in the UP position. The landing gear handle inside the cockpit was in the DOWN position but this was explained by Flightcraft personnel, who confirmed that they had placed the handle in the down position in an attempt to lower the gear as a part of recovering the aircraft after the accident.
The only damage to control surfaces were the right aileron and spoiler on the right wing.
The Corvette still had the original engines: two Pratt & Whitney Canada JT15D-4 turbo fan engines. Both engines looked undamaged and rotated freely. Fuel was found in the right engine fuel line (that is, the fuel was flowing fine) and the oil and fuel recovered were uncontaminated.
The oil temperature indicators in the cockpit did not match: the left engine oil temperature had captured at 72°C and the right engine oil temperature at less than 20°C. The oil temperature indicators are powered by 28 volts DC.
The initial inspection of the right engine found no significant problems. In fact, the only obvious visible difference between the engines was that that the right engine inlet had grass in the fan and grass seed in the bypass duct; none was found in the left engine.
Now, without looking up the incident, what do you think might have happened that morning? Let me know what you think in the comments.
(Note: If you know this case or decide to look it up, please refrain from adding information in the comments; next week I’ll share what the investigators discovered once they began their analysis back at the NTSB Office in Seattle.)
Update: The second part of this post is now posted Engine Failure Before Take-Off