Clarification: Malibu PA-46-310P or JetPROP DLX?

Many of our readers, all of them sharper than me last month, wrote to remind me that the Piper Malibu (PA-46-310P version) was delivered from the factory with a Continental TSIO-520 piston engine. Yet, in our December 2015 Cause & Circumstance, (page 56) I discussed the loss of “Malibu PA-46-310P” N87NF and mentioned the position of the cockpit condition lever and the odor of Jet A at the accident scene.

I should have identified the accident aircraft as a Malibu JetPROP DLX (Malibu PA-46-310P) a recip-to-turboprop conversion made by JetPROP LLC of Spokane, Washington. The accident aircraft engine was a Pratt & Whitney PT6A-34 turboprop. Investigators said neither the engine nor the airplane’s systems were causal factors in this loss-of-control accident.  

The airplane was destroyed and its pilot killed when it broke up in flight and crashed into trees and terrain near Dawsonville, Georgia. Night IMC prevailed for the flight and an IFR flight plan from Morristown Municipal Airport (MMU), Morristown, New Jersey, to the intended destination of DeKalb-Peachtree Airport (PDK), Atlanta.

That NTSB determined the probable cause of the accident was the pilot’s inflight loss of airplane control due to spatial disorientation while operating in dark night IMC, which resulted in the exceedance of the airplane’s design stress limitations and a subsequent inflight breakup. Contributing to the accident was the pilot’s distraction by the reported malfunction of the autopilot system.

Thank you readers for keeping me on my toes. Sorry for the confusion.

Richard N. Aarons
Safety Editor

The NTSB has become so concerned about loss-of-control (LOC) accidents that it held a symposium in October seeking solutions to the phenomenon in general aviation. While the focus seemed to be on smaller owner-flown aircraft, the sad truth is that we seem to be witnessing an epidemic of LOC accidents among all sectors — airlines, corporate and business aviation as well as general aviation.

LOC accidents are rarely complex. They usually involve a disconnect between the pilot and the real world. Sometimes modern avionics play a part in these accidents as has been the case with some highly publicized airline mishaps. But more often, crew workload, sensorial illusions and inattention are at the heart of the matter.

This month we’ll look at a typical LOC accident — the sad loss of a business pilot in the crash of his Piper PA-46-310P Malibu on Dec. 2, 2013, near Dawsonville, Georgia. The airplane broke up in flight at approximately 1919 (EST) while it was maneuvering in night instrument meteorological conditions (IMC) for approach to Atlanta’s DeKalb-Peachtree Airport (PDK). The main wreckage ended up in heavily wooded terrain about 12 mi. southeast of Gainesville, Georgia. The pilot, the Piper’s lone occupant, was killed.

The personal (FAR Part 91) flight had departed Morristown, New Jersey, Municipal Airport (MMU) at 1635 on an IFR flight plan to PDK. The pilot held a private pilot certificate with ratings for airplane single-engine land, multiengine land and instrument airplane. His most recent third-class medical certificate had a restriction to wear eyeglasses. The pilot reported flight experience on the medical application of 3,500 total hours with 50 hr. in the previous six months. Investigators were unable to determine his instrument experience.

The Flight

Takeoff, climb and en route phases were routine. Nearing his destination, the pilot checked in with Atlanta Center, and the controller verified that the pilot had the local weather information for PDK.

Then, the controller queried the pilot about the airplane heading and asked if he was able to hold the assigned airplane altitude. The pilot responded in the affirmative but added that he was having trouble with his autopilot.

The controller then issued a heading of 200 deg. and an altitude of 8,000 ft. MSL. The aircraft descended below 8,000 ft. MSL, and the controller issued a revised altitude of 7,000 ft. MSL.

Thereafter, radar contact was lost and nothing more was heard from the pilot. The last recorded radar return occurred at 1918. A witness in the area heard the airplane fly over his house and heard the engine “sputter” a bit. To the witness, the airplane sounded as if it was in an “extremely deep dive” and it seemed as if the pilot “tried to do full throttle out of the dive.” Search and rescue operations were initiated immediately and local law enforcement received emergency calls reporting an aircraft crash soon after.

Searchers located the shattered wreckage quickly. The pilot had died of multiple blunt force injuries.

Weather in the area at 1853, as observed from Gainesville Memorial Airport (GVL), included calm wind; visibility, 4 mi. in mist; ceiling overcast at 500 ft. AGL; temperature, 10C; dew point, 9C; and altimeter 29.86 in. of mercury (Hg).

The Atlanta composite reflectivity image at 1917 EST indicated that the last radar target was on the leading edge of a large area of light to moderate radar echoes — light to moderate rain showers but no thunderstorms or lightning.

The GOES-13 infrared imagery for 1915 EST indicated an extensive area of overcast nimbostratus type clouds with tops near 16,600 ft. over the area.

The Wreckage

Investigators spent a lot of time examining the wreckage. The main portion of the airplane impacted trees approximately 30 ft. AGL and then crashed on the ground inverted. The wreckage path from the initial component found to the main wreckage was about 2,000 ft. long on a 220-deg. heading. An odor similar to Jet-A fuel was noted in the field where several components of the airplane were located and at the site of the main wreckage. There was no fire.

The cockpit exhibited extensive vertical crush damage. The engine controls were intact. The power lever and propeller lever were in the full forward position. The condition lever was in the midrange position.

Both yokes remained attached to the control column. The top left section of the right front seat was deformed down and aft. The top right section of the left front seat was deformed slightly aft and down. The lap belts and shoulder harnesses of the front seats did not exhibit web stretching or deformation. In addition, all seat belts remained attached to their respective attach points. A pair of eyeglasses was discovered in the forward section of the cabin. Flight control continuity was confirmed from the cockpit to all flight control surfaces through tensile overload breaks. All seats remained attached to their respective cabin area structure.

The fuselage came to rest inverted beneath the initial tree impact point. The top portion of the fuselage exhibited vertical crush damage.

The engine cowling remained attached. The nose gear was in the retracted position. Three of the propeller blades remained attached to the propeller flange. The forth propeller blade was located in dirt underneath the propeller flange and it exhibited S-bending. An undeterminable amount of fluid that smelled similar to Jet-A fuel was drained from the header tank just aft of the firewall.

The Continental 310-hp engine remained attached to the firewall through wires and all engine mounts. Examination uncovered no evidence of pre-impact failure.

The wings told the story. The outboard 10-ft. section of the right wing was located along the debris path about 700 ft. from the main wreckage in the field. The wing spar was bent in the negative direction. The inboard approximate 7 ft. remained attached to the fuselage and exhibited crush damage about 1 ft. from the fuselage. The inboard section of the right aileron was separated from the wing and located 2,000 ft. east northeast from the main wreckage. The flap was in the retracted position. The outboard section of the wing contained an undeterminable amount of fuel. The right main landing gear remained attached to the right wing in the retracted position.

The outboard 15-ft. section of the left wing was found separated from the fuselage and located in a field about 700 ft. from the main wreckage. The wing spar was bent in the negative direction. The inboard section of the left aileron remained attached to the outboard section of the wing. The left flap was separated from the wing. The flap was discovered in the retracted position. Flap control continuity was confirmed for the flaps even though the control rod separated from the flap motor assembly in tensile overload. The aileron was separated and cable continuity was confirmed from the base of the control column to the associated fracture points out to the aileron. The left main landing gear remained in the up and locked position.

The aft section of the fuselage was separated at the aft pressure bulkhead. The left and right horizontal stabilizer were separated from the empennage and found in the field 700 ft. from the main wreckage. The left and right midsection of the elevator were separated and found along the debris path, on a road approximately 900 ft. from the main wreckage. The rudder was found in the field located 700 ft. from the main wreckage. The vertical stabilizer was located next to the road approximately 850 ft. from the main wreckage. The two static ports located of the aft right side of the fuselage were free and clear of debris.

Safety Board Tests

The airplane was equipped with a Bendix/King KFC 150 flight control system, which consisted of a three-axis autopilot system with a flight computer. According to the KFC 150 operating manual, the flight director’s computer calculated the appropriate pitch and roll attitudes required to intercept and maintain headings, courses, approach paths, pitch attitudes and altitudes. Once computed, the commands were displayed to the pilot, who could elect to follow instrument command bars or couple the signals to autopilot servos.

The General Emergency Procedures section of the autopilot operating handbook indicated:

(1) Disengage autopilot/yaw damp.

(a) Simultaneously regain control of aircraft and hold down Autopilot Disconnect Trim Interrupt button.

(b) Pull autopilot circuit breaker.

(c) Release autopilot disconnect/trim interrupt button.

The autopilot system from the airplane was sent to the manufacturer for testing under FAA supervision. The examination revealed that the yaw servo, pitch servo and roll servo tested without any anomalies noted. Both the roll and pitch servo mount slip clutches measured below the tolerance limits for the testing procedures. The yaw servo mount slip clutch was tested without any anomalies noted. The directional gyro was functionally tested with no anomalies noted.

A Garmin GPSMAP 696 handheld GPS, a Garmin 496 handheld GPS, an Avidyne EX500 and an engine monitor were located, removed and sent to the NTSB Recorder Laboratory for data download. The Garmin GPSMAP 696 contained data that began at 1610 and continued until 1919. The last recorded data points indicated that the airplane was on a direct course to PDK, made a slight left turn and then a right turn approximately 180 deg. away from the track toward PDK at 1916. Then, it made a turn back to the left approximately 360 deg. and continued the bank and began a descent until the data points ended.

A trajectory study and a performance study were performed using GPS data and ATC data in order to determine the altitude of the inflight breakup of the airplane. An airplane performance history was developed using airplane characteristics, atmospheric data, and recorded radar and GPS data.

It seems the airplane had descended to about 8,000 ft. MSL and had a ground speed of about 175 kt. when it started the slight turn to the left. The study determined that in the final maneuver, the airplane descended from about 8,000 ft. MSL to approximately 2,200 ft., accelerated to about 300 kt. of indicated airspeed, and broke up in 18 sec.

According to the manufacturer’s flight manual, the airplane’s maximum operating limit speed (Vmo) was 172 kt., and its design maneuvering speed (Va) was 137 kt. at maximum gross weight.

Although post-accident testing revealed no anomalies with the autopilot system, “the pilot should have been able to disable the autopilot if it was experiencing a problem and then continue to fly the airplane,” said the Safety Board. “However, given the available data and his conversation with the controller, it is likely that the pilot became focused on the autopilot system and diagnosing the reported problem. Dark [moonless] night conditions prevailed for the flight, and, about the time of the accident, instrument meteorological conditions with restricted visibility due to rain prevailed. Given the pilot’s distraction, the weather conditions encountered during the flight and the sustained descending left turn, it is likely that the pilot experienced spatial disorientation and then lost control of the airplane.”

The Safety Board determined the probable cause of this accident was “the pilot’s inflight loss of airplane control due to spatial disorientation while operating in dark night instrument meteorological conditions, which resulted in the exceedance of the airplane’s design stress limitations and a subsequent inflight breakup. Contributing to the accident was the pilot’s distraction by [a] reported malfunction of the autopilot system.”

It would seem that it all gets down to the basics — believe your instruments and keep up a rapid scan, especially when reconfiguring avionics and instrumentation. 

And finally, nothing is more important than flying the airplane — neither communications nor navigation. Maintaining spatial and situational awareness is always the pilot’s primary task.

This article appears in the December 2015 issue of Business & Commercial Aviation with the title "Malibu Pilot's Loss of Control."