But Lists The Problem As The Probable Cause Of A March 2010
Fatal Accident
It will be one of those accidents that remains largely
unexplained. The pilot of a Piper Malibu reported to ATC that the
airplane's controls were locked up, but an investigation by the
NTSB could not find a reason for such a problem. Based on the
statement by the pilot before the accident, and of a survivor
during the investigation, the cause of the accident was listed as a
control malfunction.
NTSB Identification: ERA10FA195
14 CFR Part 91: General Aviation
Accident occurred Tuesday, March 30, 2010 in Roanoke, VA
Probable Cause Approval Date: 06/13/2011
Aircraft: PIPER PA46, registration: N6913Z
Injuries: 1 Fatal,1 Serious.
About one minute after takeoff, the pilot reported to the air
traffic controller that the airplane's control wheels were locked.
The controller subsequently cleared the pilot to land on any
runway. No further transmissions were received from the pilot and
the airplane continued straight ahead. Witnesses observed the
airplane in a slow, level descent, until it impacted wires and then
the ground. During a postaccident examination of the airplane,
flight control continuity was confirmed to all the flight controls.
Due to the impact and post-crash fire damage, a cause for the
flight control anomaly, as reported by the pilot, could not be
determined; however, several unsecured cannon plugs and numerous
unsecured heat damaged wire bundles were found lying across the
control columns forward of the firewall. Examination of the
airplane logbooks revealed the most recent maintenance to the
flight controls was performed about four months prior to the
accident. The airplane had flown 91 hours since then.
The NTSB determined that the probable cause of the accident was
a malfunction of the flight controls for undetermined reasons.
According to the manager of an FBO at KROA, the pilot and
passenger arrived at KROA around 0930 on the morning of the
accident. They had flown into KROA from Charlottesville-Albemarle
Airport (CHO), Charlottesville, Virginia, for a meeting with the
manager of the FBO. They completed their meeting, had lunch, and
then prepared for the return flight to CHO.
The passenger was interviewed in the hospital after the
accident. He stated the takeoff seemed normal; however, he was
seated in a rearward facing seat in the back of the airplane. The
passenger reported at some point after takeoff, the airplane made a
"flat" right turn and the pilot stated, "I have a problem." The
passenger remembered hearing a "clunk" from the right side during
the flight but could not recall when. He did not remember the
impact, but was conscious afterward and was able to exit the
airplane through the passenger door.
Several employees of the FBO were inside at the time the
airplane departed, and were monitoring the air traffic control
tower radio frequency. They heard the pilot announce over the
radio, "my controls are locked," and they subsequently went outside
to observe the airplane.
They observed the airplane above runway 24, near the
intersection of runway 33. They estimated the airplane was at an
altitude of 150-300 feet. They observed the airplane then begin a
"slight right turn" and described the airplane traveling slowly.
They lost sight of the airplane behind terrain as it continued to
descend. Seconds later they observed smoke in the vicinity of where
the airplane was descending.
One of these witnesses from the FBO, who was also a pilot,
reported the airplane's attitude as a shallow, "flat," right bank.
He stated the airplane was moving slowly with a "minimal sink
rate." The witness also stated that although the airplane was
turning to the right, he did not observe the airplane's wings "dip"
at all. The descent remained relatively "flat," until he lost site
of the airplane behind terrain.
Another witness was driving on a road near the airport when he
observed the airplane in a level attitude (not climbing or
descending) as it passed overhead. As the airplane passed his
position, it was "rocking a little left and right" and then began
to bank to the right. The witness stated the airplane was moving
"relatively slow...just fast enough to maintain its level
attitude." Shortly after, the witness observed the airplane strike
a wire with its right wing and then "cartwheel" before it impacted
the ground near a building.
According to air traffic control information provided by the
FAA, the pilot was cleared for takeoff from runway 24. About 1
minute later, the pilot reported, "I got a problem…the ah
control wheels are locked." The controller subsequently cleared the
pilot to "land on any runway." No further transmissions were
received from the pilot.
Pilot Information
The pilot held a private pilot certificate with ratings for
airplane single-engine land, multiengine land and instrument
airplane. His most recent FAA third class medical certificate was
issued on December 3, 2008. At that time, he reported 3,000 hours
of total flight experience.
According to paperwork provided by the pilot’s family, his
most recent flight review and instrument proficiency check were
completed on May 24, 2009.
The pilot's family also provided a printout of the pilot's
computerized logbook, with entries from November 21, 2008 to
February 28, 2010. The total flight time accumulated during that
period was 110.5 hours, in the accident airplane and another
PA46-310P.
The pilot also attended “Factory JetPROP DLX ground school
of 8 hours and flight training program of 5 hours, including
pre-flight and post flight training, flight training, landings,
emergency procedures and night flight.”
Piper Malibu File Photo
Aircraft Information
The accident airplane was a low-wing, single engine airplane,
manufactured in 1985. The airplane was powered by a Teledyne
Continental TSIO-520 engine. According to the co-owner of the
airplane, he and the accident pilot had owned the airplane for
about 7 years.
Examination of the airplane and engine logbooks revealed the
most recent annual inspection was completed on May 20, 2009 at a
recorded time of 855 hours. Examination of the hobbs meter at the
accident site revealed a time of 956 hours.
The aircraft logbook (labeled “logbook #2) contained
entries from August 6, 1999 to November 25, 2009. Examination of
the entries in the aircraft logbook and maintenance paperwork
revealed the following entries regarding the flight controls:
March 14, 2007, (annual inspection) “…left hand
aileron pulleys aft of pitot tube frozen/forward cable off
pulley…removed cable guard, lubed and freed pulleys,
installed cables on pulleys, reinstalled guard and ops checked, no
defects noted at this time..”
March 31, 2008, (annual inspection) “…pilots and
co-pilots yoke shafts require lube…lubed pilots and copilots
yoke shafts with LPS #2….pilots forward elevator stop not
hitting…adjusted secondary elevator stop in accordance with
PA-46-310 AMM.”
July 17, 2008: “…found and fixed broken wires at
pilot yoke under instrument panel.”
September 18, 2009: “…left aileron damaged while
towing…removed damaged aileron and installed loaner
aileron…”
November 25, 2009: “…removed loaner aileron and
installed factory new aileron balanced and painted…”
The Hobbs time on this date was recorded as 864.7 hours.
The Hobbs meter at the accident site indicated 956.3 hours.
Wreckage Information
The initial impact point (IIP) was a wire which was
approximately 50 feet tall, and stretched from two posts. Located
under the wire was a small piece of aircraft fuselage skin.
Approximately 37 feet from the IIP, three ground scars were
observed that corresponded with the dimensions of the three
propeller blades from the airplane. One of the propeller blades was
buried in the ground scar. The remaining two propeller blades were
lying adjacent to the ground scars.
All three propeller blades were separated from their respective
hub sockets at the root of the blade. Two of the three blades
displayed chordwise scratching on the leading edges of the
blades.
The wreckage path was oriented 340 degrees magnetic, and
extended approximately 62 feet to the main wreckage. The main
wreckage came to rest about 25 feet from the propeller ground
scars, upright, at the corner of an industrial building. All
components of the airplane were accounted for in the vicinity of
the main wreckage, and the airplane was oriented 230 degrees
magnetic. The airplane was consumed by a post-crash fire, with the
exception of the left aileron.
The right wing was separated at the wing root; however, it
remained attached to the fuselage through the flight control
cables. The right aileron and flap were present in their respective
positions on the wing; however, they were completely consumed by
the post-crash fire.
The left wing remained attached to the fuselage at the wing
root. The inboard section of the wing was twisted and came to rest
at a 90 degree angle to the root, with the leading edge resting on
the ground. The outboard section came to rest upright. The left
flap remained attached to the wing; however, it was completely
consumed by the post-crash fire. The left aileron was separated
from the wing and located about 15 feet in front of the main
wreckage. The aileron was intact and did not sustain any fire
damage.
The tail section was separated from the fuselage; however it
remained attached through flight control cables. The left and right
horizontal stabilizers sustained severe post-crash fire damage.
The elevator and rudder flight control cables remained attached
to the respective flight controls and were traced through the
floorboard to their appropriate attachments on the control column
and rudder pedals. No obstructions were noted on the flight control
cables. The left and right side aileron cables were connected to
the control column and traced to the wing roots where they were
separated. Examination of the control cable ends revealed
overstress separation.
The pilot and co-pilot control yokes were initially unable to be
rotated on scene, due to a misalignment of the stop bracket, which
was damaged during the impact. Examination of the area around the
pilot and co-pilot control columns on the forward side of the
firewall, revealed several unsecured cannon plugs in the vicinity
of the control yokes. One cannon plug connector half was noted to
be dangling across the co-pilot's control column. Additionally,
numerous heat damaged wire bundles were lying across the control
columns.
The engine was separated from the airplane and came to rest
underneath it. After removal from the accident site, a 24-volt
battery was directly attached to the starter, and valve train
continuity and thumb compression was confirmed on all cylinders.
The cylinders were examined with a lighted borescope, and no
anomalies were noted. The top spark plugs were removed and they
exhibited "normal" wear when compared to the Champion Check-A-Plug
comparison card.
The fuel pump was removed from the engine and the drive shaft
was free to rotate. Disassembly of the fuel pump revealed no
internal damage. Fuel was observed in the fuel pump and fuel
manifold. All of the fuel injection nozzles were undamaged, and
clear of debris. The oil pump was disassembled and the housing
displayed no evidence of hard particle passage.
Tests and Research
The Engine Data Monitor (EDM) device was sent to the NTSB
Vehicle Recorder Laboratory for examination. According to the
Specialist's Factual Report, the device was significantly damaged
by fire during the accident; however the device's non-volatile
memory was able to be extracted.
The data extracted included flights from December 30, 2009 to
March 30, 2010. Examination of 13 engine parameters downloaded from
the unit, for two flights on the day of the accident, revealed no
pre-impact mechanical anomalies.
A section of the pilot's control column was retained and sent to
the NTSB Material's Laboratory for examination. According to the
Investigator's Factual Report, the section of control column was
severely damaged by fire. The bearing which provides for the
rotational capability of the control column was found to be
difficult to rotate and felt rough when it was rotated. The bearing
was removed from the control column and was initially examined
externally and then internally by sectioning the bearing's body and
races. The external examination revealed that the bearing had
become contaminated with debris such as soot, resolidified molten
plastic, and other particulates consistent with fire debris. When
the bearing was sectioned and examined under the stereo microscope
it was determined that the bearing balls were all intact with no
obvious deformation. The bearing balls had become oxidized and some
had thermal discoloration consistent with a high temperature
exposure. The bearing races had an overall appearance of high
temperature exposure exhibited by thermal discoloration of the
metal. There was no evidence to suggest that the bearing was not
functioning properly prior to the high temperature exposure.
Additional Information
The airplane was last fueled on the morning of the accident,
with 25 gallons of 100LL aviation fuel in each fuel tank, prior to
departing CHO. The accident airplane was involved in a previous
accident on November 11, 2008 (NTSB Accident ID: ERA09CA065).
According to the co-owner of the airplane, during takeoff he was
“correcting to the right, when the airplane departed the
runway and ran into a ditch.” The co-owner reported no
mechanical anomalies with the airplane and there was “nothing
wrong with the flight controls.” The NTSB determined the
probable cause of the accident was, “the pilot’s
failure to maintain directional control during takeoff.
Contributing to the accident were gusting crosswinds.”
A search of the FAA Service Difficulty Report (SDR) database
revealed no relevant reports of flight control anomalies with the
PA-46-310P. Additionally, a query of the airplane manufacturer
revealed only one type of flight control anomaly report for the
PA-46-310 series. The report described a 2006 model PA 46-350P,
which experienced aileron stiffness and the autopilot failed to
disengage in-flight. Examination of the subject airplane revealed
the left aileron sector was frozen, due to corrosion in the needle
bearing.
As a result of the submitted field report, Piper issued a
Maintenance Alert to PA-46 owners and operators, which clarified
the lubrication requirements of the aileron sector. The aileron
sectors in the accident airplane were examined for evidence of this
anomaly, but none was observed.