HISTORY OF FLIGHTOn January 22, 2015, about 0913 eastern standard time, a Piper PA-23, N465JA, registered to 55XRAY, Inc., and operated by Tailwheels, Etc., descended into a building northwest of the Lakeland Linder Regional Airport (LAL), Lakeland, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 local, instructional flight. The airplane was destroyed and the flight instructor and pilot-rated student were fatally injured. The flight originated about 0847 from LAL.

Personnel of the operator reported the purpose of the flight was training for the pilot-rated student, who intended to add a multi-engine rating to his private pilot certificate. The flight, which was the 7th lesson, was scheduled between 0800 and 1000 hours. One typical procedure to perform during the 7th lesson was an engine shutdown (typically the right) and to feather the right propeller. In that scenario, the flight would depart LAL and proceed to the north while climbing to between 3,000 and 4,000 feet mean sea level (msl). The flight would then return and when over LAL, the right engine would be secured and the right propeller would be feathered.

Security video from the operator depicted the pilot-rated student walking to the airplane and an employee of the operator reported watching him from the window perform a preflight inspection. The same individual also reported watching the flight instructor inspect the airplane. Another flight instructor with the operator, who was parked on the ramp next to the accident airplane, also observed the pilot-rated student performing a walk around of the accident airplane, noting he added oil to the left engine. The flight instructor who witnessed the preflight inspection reported he did not see anything "out of order" and the pilot-rated student did not ask or mention anything to him as he was standing nearby. Because of the resolution of the security video, seating positions could not be detected.

The accident airplane then taxied to another spot on the ramp east of the parked location, and turn to a northeast direction. The airplane remained on that spot for 2 minutes 46 seconds. According to air traffic control (ATC) chronological summary of flight communications and voice communications, a flightcrew member contacted ground control and requested taxi to the active runway with a northbound departure. The controller cleared the flight to taxi to runway 05 via Echo, and about 0847, the local controller cleared the flight for takeoff; portions of the taxi and about 13 seconds of the takeoff were recorded by security video.

According to uncorrelated radar data, at 0849:48, an airplane with a transponder code of 1200 appeared about 1.3 nautical miles and 020 degrees from the departure end of runway 05; altitude was not reported. The airplane proceeded in a northerly direction and about 0850:00, the flightcrew were advised by the local controller that frequency change was approved. There was no further communication with the flight crew of the accident airplane. The uncorrelated radar data indicated that the airplane proceeded north of the airport where changes in direction consistent with airwork were performed; altitude was not reported for several of the radar targets. Following the airwork, the airplane flew in a southerly direction towards LAL.

Closer review of the radar data revealed at 0911:43, while north of I-4, the airplane was at 3,600 feet msl, while no altitude was reported at the next secondary return observed 5 seconds later, or for the remainder of the 14 secondary returns. A witness who was located approximately 1.8 nautical miles and 032 degrees from the accident site, reported seeing the airplane when it was north of I-4 flying in a southbound direction at what he estimated was 10,000 feet; the sound was what directed his attention. He noticed the airplane was flying level, and heard 2 pops from the engine(s). The second "pop" sound was louder than the first, and he reported that the engine "quit." The airplane continued in a southerly direction until about 0912:29, or just south of I-4, at which time a change to a southwesterly direction was noted. The airplane continued on the southwesterly heading until the last radar target at 0912:57, about 1,443 feet and 047 degrees from the accident site.

The witness who was located about 2 miles northeast of the accident site reported that a couple seconds after the second "pop" sound, the airplane "nose-dived" and descended steeply. He heard an explosion and saw large black smoke. He reported seeing puffs of gray or black colored smoke from the engine(s) when he heard the "pop" sound, but also stated that he saw the puffs of smoke from the airplane while it was in a nose-down attitude.

Another witness who was driving on Polk Parkway in a southbound direction, about 1,500 feet and 072 degrees from the accident site, with the windows up noticed a light colored airplane "heading to do a stunt" in what he described as a nose-down attitude. At about 400 to 600 feet, he saw something about the size of the front wheel separate from the front of the airplane, or the airplane could have hit a bird; he could not describe the color of the item that he saw separating from the airplane. He did not observe the ground impact because trees obscured his view, and noticed smoke. He pulled off the road and called 911 to report what he had seen. He indicated the weather conditions at the time consisted of sunny conditions, no clouds, and breezy. He confirmed the airplane was not spinning when he saw it, and he did not see any smoke trailing the airplane. The airplane crashed west of his position, and he could not hear any sounds from the engines.

Two witnesses who were located on the property where the airplane crashed, or about 2,050 feet and 315 degrees from the accident site location, both reported seeing the airplane. One witness reported hearing the airplane travelling from north to the south, and she heard, "…a very loud/unusual engine sound coming from the plane." She looked to the east-southeast, and witnessed the airplane descending in a vertical direction with the nose, "in a dive position." After a few seconds, she heard an explosion and saw black and gray colored smoke at the tops of the trees. She realized the airplane had crashed and called 911 to report the accident. The other witness reported she was looking to the east, and heard a loud engine noise from an airplane that was travelling from the north to the south. She reported the engine noise got louder as the airplane descended nose first to the ground. She heard an impact and smoke immediately followed. She also called 911 to report the accident.

Security cameras captured video depicting the final portion of the airplane's descent and subsequent post-impact fireball. The cameras were located about 0.50 nautical mile and 245 degrees from the accident site. The video was provided to the NTSB for analysis. PERSONNEL INFORMATIONThe flight instructor, age 61, held an airline transport pilot (ATP) certificate with an airplane multi-engine land rating. On the ATP certificate he was type rated in a RA390S, issued November 26, 2011. He held a commercial pilot certificate with an airplane single engine land rating, and also held a flight instructor certificate with airplane single engine, airplane multi-engine, and instrument airplane ratings; the multi-engine rating was issued on June 27, 2014. He held a 2nd class medical certificate with a limitation to wear corrective lenses issued July 16, 2013.

According to personnel employed by the operator, the flight instructor was hired approximately 5 years prior to the accident.

A review of his pilot logbook, which contained entries from January 1, 2014 through January 21, 2015, revealed he logged a total time of 6,609 hours. Of the total time, about 2,520 hours were in multi-engine aircraft. Between January 1, 2014 and January 21, 2015, he logged about 60 hours in the accident airplane. Since adding a multi-engine rating to his flight instructor certificate in June 2014, he logged 44.4 hours as an instructor in the accident airplane.

The pilot-rated student, age 40, held a private pilot certificate with an airplane single engine land, and instrument airplane ratings, and held a second class medical certificate with no limitation issued November 26, 2014.

A review of the pilot-rated student's logbook, which contained entries from September 29, 2007 to January 21, 2015, revealed he logged a total time of 333.0 hours. Excluding the accident flight, he logged a total of 6 flights in the accident airplane, accruing a total of 7.6 hours. Of the 6 flights, all were flown with the accident flight instructor. AIRCRAFT INFORMATIONThe airplane was manufactured in 1957 by Piper Aircraft, as model PA-23, and was designated serial number 23-1033. It was powered by two 150 horsepower Lycoming O-320-A1B engines and equipped with Hartzell HC-C2YL-2CUF constant speed propellers installed in accordance with Supplemental Type Certificate (STC) SA00721CH.

Maintenance records before 2009 were not available for the airframe, engines, or propellers. Review of the maintenance records revealed the airplane was last inspected in accordance with an annual inspection on December 15, 2014. The airplane total time at that time was reported to be 5,922.1 hours. Although the hour meter was destroyed, the hour meter at the end of the last flight before the accident flight was 5,936.8 hours, or an elapsed time of 14.7 hours since the last annual inspection was performed.

On December 8, 2014, or about 7 days before the last annual inspection was completed, personnel of the FAA Flight Standards District Office in Orlando, Florida, conducted a ramp inspection and maintenance records review of the operator's airplanes and facility; the ramp and records inspection included an inspection of 5 airplanes which included the accident airplane. Correspondence between the FAA and the operator dated December 12, 2014, indicated that with respect to the accident airplane, a cracked baffle in the right engine compartment was noted, and fuel appeared to be seeping from the fuel cap inboard right fuel tank. On January 9, 2015, the operator submitted a letter to the FAA indicating that with respect to the accident airplane, the cylinder baffle was repaired and the right fuel cap and surrounding area was cleaned and inspected for leaks but none were found; new gaskets were ordered. A review of the airframe logbook revealed an entry dated December 23, 2014, indicating a new right main fuel cell was installed.

The airplane was flown the day before by a pilot-rated student and the accident flight instructor during a training flight. The pilot-rated student reported that after departure from Lakeland, they performed airwork consisting of steep turns, slow flight, power-on and power-off stalls, several simulated engine out and velocity minimum control air (Vmca) demonstrations. They also performed a simulated single engine ILS approach to runway 9 at LAL. She reported that the airplane "flew flawlessly", and indicated she is a commercial pilot, flight instructor, and airframe and powerplant mechanic with inspection authorization. The flight duration was reported to be 0.9 hour. METEOROLOGICAL INFORMATIONA surface observation weather report taken at LAL at 0850, or approximately 23 minutes before the accident indicated the wind was from 080 degrees at 3 knots, the visibility was 7 statute miles, and scattered clouds existed at 12,000 feet. The temperature and dew point were 18 and 17 degrees Celsius, respectively, and the altimeter setting was 30.20 inches of mercury. The accident site was located about 2 nautical miles and 326 degrees from the center of LAL. AIRPORT INFORMATIONThe airplane was manufactured in 1957 by Piper Aircraft, as model PA-23, and was designated serial number 23-1033. It was powered by two 150 horsepower Lycoming O-320-A1B engines and equipped with Hartzell HC-C2YL-2CUF constant speed propellers installed in accordance with Supplemental Type Certificate (STC) SA00721CH.

Maintenance records before 2009 were not available for the airframe, engines, or propellers. Review of the maintenance records revealed the airplane was last inspected in accordance with an annual inspection on December 15, 2014. The airplane total time at that time was reported to be 5,922.1 hours. Although the hour meter was destroyed, the hour meter at the end of the last flight before the accident flight was 5,936.8 hours, or an elapsed time of 14.7 hours since the last annual inspection was performed.

On December 8, 2014, or about 7 days before the last annual inspection was completed, personnel of the FAA Flight Standards District Office in Orlando, Florida, conducted a ramp inspection and maintenance records review of the operator's airplanes and facility; the ramp and records inspection included an inspection of 5 airplanes which included the accident airplane. Correspondence between the FAA and the operator dated December 12, 2014, indicated that with respect to the accident airplane, a cracked baffle in the right engine compartment was noted, and fuel appeared to be seeping from the fuel cap inboard right fuel tank. On January 9, 2015, the operator submitted a letter to the FAA indicating that with respect to the accident airplane, the cylinder baffle was repaired and the right fuel cap and surrounding area was cleaned and inspected for leaks but none were found; new gaskets were ordered. A review of the airframe logbook revealed an entry dated December 23, 2014, indicating a new right main fuel cell was installed.

The airplane was flown the day before by a pilot-rated student and the accident flight instructor during a training flight. The pilot-rated student reported that after departure from Lakeland, they performed airwork consisting of steep turns, slow flight, power-on and power-off stalls, several simulated engine out and velocity minimum control air (Vmca) demonstrations. They also performed a simulated single engine ILS approach to runway 9 at LAL. She reported that the airplane "flew flawlessly", and indicated she is a commercial pilot, flight instructor, and airframe and powerplant mechanic with inspection authorization. The flight duration was reported to be 0.9 hour. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed the airplane crashed into a concrete building, and the building and the contents of it were destroyed. The accident site was located approximately 2.4 nautical miles and 326 degrees magnetic from the center of LAL.

According to personnel of the Lakeland Police Department, a black colored bag containing a study guide for the accident airplane, a pilot logbook, and over the counter pain relief medication was found near the accident site. The bag was associated with the pilot-rated student, and was removed from the site and secured before NTSB arrival. The bag was located approximately 459 feet and 13 degrees from the crash site. Examination of the bag revealed evidence of wear in several areas, but no evidence of fire was noted on the bag exterior or interior items. Law enforcement personnel also performed aerial and ground searches of the outlying area and no other aircraft parts were identified.

Further examination of the area surrounding the accident site revealed a piece of rudder with rudder trim tab attached was located approximately 138 feet and 7 degrees from the accident site. Examination of the part revealed no evidence of fire; evidence of over travel of the upper hinge was noted on both sides of the rudder. The upper hinge remained attached and a portion of the vertical stabilizer aft spar remained attached to the hinge (45 degree shear lips of the fracture surfaces were noted). The leading edge from the upper hinge below was displaced to the left approximately 60 degrees. The full span of the trim tab remained attached, but the piano wire was extended about 1 inch at the bottom and several of the hinges were not secured. The lower portion of the forward spar was torn (45 degree shear lips), and the aft spar was fractured at the lower end of the trim tab (also 45 degree shear lips). The trim tab actuator control rod was pulled from the trim tab.

The portion of the instrument panel, and avionics was located inside the building in the southwest corner. Examination of the instrument panel revealed it contained the rudder torque tube, rudder control pedals, control column, left control yoke, electrical wiring, sections of flight control cables, nose landing gear actuator, and throttle quadrant. Examination of the throttle quadrant revealed no cables were attached, and no determination could be made as to the pre-impact positions of the controls.

Components located immediately outside the building consisted of wingtip fairings, section of left elevator, section of right aileron, and aluminum skin. Tubular structure removed from the building was retained for further examination.

Examination of the rudder torque tube which was structurally separated revealed the left rudder control cable was fractured approximately 104.25 inches from the rudder torque tube attach point, or at fuselage station (FS) 153.25. The cable was separated from the rudder torque tube attach point; a portion of the fractured piece of aluminum remained attached to the cable. Further examination of the left rudder control cable clevis revealed slight deformation from the side direction. The right rudder control cable remained attached to the attach point on the torque tube, but the cable was fractured approximately 46 inches from the attach point. The left rudder control cable was retained for further examination by the NTSB Materials Laboratory.

Examination of the airframe revealed that with the exception of the rudder and attached trim tab and left elevator that were found away from the impact site, all structure, primary, and secondary flight controls aft of FS 168.5 were not identified. The right wing was also not identified, and only an approximate 5 foot section of left wing with left main landing gear trunnion, actuator, and engine mount was recovered. Identifiable tubular structure between fuselage station (FS) 91.25 and 168.5 was noted to have multiple fractures. The tachometer which was loose in the recovered wreckage was examined which revealed the left needle remained attached and was found positioned to approximately 1,200, while the right needle was separated.

Examination of the left side tubular structure revealed a 0.875 inch diameter vertical oriented tube that runs from FS 168.5 to 153.875 was fractured approximately 15.5 inches from the cluster at FS 168.5. Both sides of the fractured tube were retained for further examination by the NTSB Materials Laboratory. The 45 degree down/forward tube was fractured and exhibited "D" shape at the fracture approximately 16 inches as measured from the cluster; the tube was slightly bent. The angle attach bracket remained attached at FS 168.5 by a bolt, nut; the attaching rivets were sheared. Two horizontal oriented tubes on the left side at FS 153.875 exhibited missing wall thickness within several inches of the cluster at FS 153.875, and were fractured approximately 9 inches from the cluster.

Examination of the right side tubular structure at FS 168.5 revealed 3 tubes were attached at the cluster and three tubes were fractured at the cluster. The horizontal tube spanning from the right to the left side of the airplane exhibited a "D" shape fracture approximately 26 inches from the cluster. One tube was fractured and deformed at the cluster, and one tube was fractured within inches of the cluster.

Examination of the left engine revealed the crankcase was fractured and partially consumed in the post impact fire. The oil sump and the accessory case were fire destroyed, and all of the rear mounted accessories were fire destroyed and could not be operated. The No. 2 cylinder was separated from the engine and partially consumed. The camshaft was separated from the engine and not observed among the recovered wreckage. Continuity of the crankshaft to the rear gears and to the connecting rods was observed through the openings in the crankcase. The rocker covers were removed and no damage other that fire or impact damage noted to the valves. The carburetor and the engine driven fuel pump were separated from the engine and destroyed in the post-impact fire. The starter, alternator and vacuum pump were separated from the engine. The starter was not observed, and the alternator and vacuum were fire damaged.

Examination of the ignition system components of the left engine revealed the magnetos were separated from the engine, and the ignition harness was destroyed by the postcrash fire. It could not be determined which magneto was the left or the right. On the magneto serial number 10080567, the case half screw near the "P" lead attach stud appeared to be backed out about 3/8 inch and was bent. The screw was removed and the threads on the screw and in the corresponding case half threaded hole observed undamaged. No determination could be made if the screw contacted the "P" lead stud. All of the sparkplugs were damaged or unobserved except the Nos. 2 and 4 bottom; those sparkplugs exhibited undamaged electrodes. The Nos. 3 and 4 lower sparkplugs had fine wire electrodes, while the observed sparkplugs had massive electrodes.

Examination of the lubricating system components of the left engine revealed the oil sump was destroyed and the oil suction screen not observed. The oil filter element was charred and no metallic debris was observed between the folds in the filter media. The oil cooler and oil cooler hoses were fire destroyed.

Examination of the right engine revealed the outer portion of the crankshaft flange was separated and remained with the propeller. The No. 2 cylinder head was impact damaged and separated from the cylinder barrel. All of the rear mounted accessories were fire destroyed and could not be operated. Fire damage prevented rotation of the crankshaft. The cylinders were removed and continuity of the crankshaft to the rear gears and to the valve train was visually confirmed. The rocker covers were removed and no damage other that fire or impact damage noted to the valves. The carburetor and engine driven fuel pump were separated from the engine and fire destroyed. The starter remained attached to the engine and was impact and fire damaged. The alternator and vacuum pump were impact separated from the engine and fire damaged.

Examination of the ignition system components of the right engine revealed the left magneto remained attached, and the securing hardware for the right magneto was in-place which entrapped portions of the housing, but the right magneto a portion of which was recovered was not in place. Both magnetos and ignition harness were destroyed by the postcrash fire. Seven spark plugs were identified; all but one were the massive electrode type. All top spark plugs (3) were impact and fire damaged, while the bottom exhibited heat damage. Closer review of the bottom plugs revealed the No. 1 cylinder electrode exhibited normal undamaged condition, the No. 2 cylinder sparkplug was contaminated with material like ash, the No. 3 cylinder sparkplug was water soaked, and the No. 4 cylinder sparkplug had extensive white colored contamination.

Examination of the lubricating system components of the right engine revealed oil was observed on the engine internal components. The oil suction screen, oil cooler and oil cooler hoses were fire destroyed. The oil filter element was charred and no metallic debris noted between the folds of the filter media.

Examination of the propellers revealed both had separated from the respective engine mounting flange and fire and impact damage to both precluded actuation of their pitch change mechanisms.

Examination of the left propeller as first viewed revealed the propeller blades were in the normal operating range; one counterweight had punctured the spinner dome in a low blade angle position. About 8 inches of the tip of one propeller blade was missing and the other blade was fractured about 18 inches from the blade butt. The cylinder was stripped from the hub and had to be cut off at the pitch change rod for access to the hub; the piston was jammed inside the cylinder and could not be observed. The fork was intact. The feathering spring could not be observed as it was jammed inside the cylinder. The "A" preload plate had an impression mark from the "B" blade knob, which indicated that the propeller was at approximately 15 degrees at impact (low blade angle setting was 11.8 degrees). The "B" preload plate had an impression mark from the "A" blade knob, which indicated an extreme reverse position of -25 degrees. Several scratches and marks indicating this impression mark were made during the impact sequence.

Examination of the right propeller as first viewed revealed the propeller blades were in the normal operating range; one counterweight had punctured the spinner dome in a low blade angle position. Both propeller blades were missing half of their blade length. The cylinder dome was fractured all the way around, and the piston was jammed inside the cylinder and could not be observed. The pitch change rod appeared to be intact but could not be fully inspected as it was jammed inside they cylinder as well. The hub assembly was intact; however the cylinder could not be removed due to being fractured at the top. The "B" preload plate had an impression mark from the "A" blade knob that indicated the blade was at 15 degree blade angle at impact (low blade angle setting was 11.8 degrees). The "A" preload plate had no impression marks. MEDICAL AND PATHOLOGICAL INFORMATIONPostmortem examinations of the flight instructor and pilot-rated student were performed by the District 10 Medical Examiner's Office, located in Winter Haven, Florida. The cause of death for both was listed as multiple blunt force traumatic injuries.

Forensic toxicology of available specimens of the flight instructor and pilot-rated student were performed by the FAA Bioaeronautical Sciences Research Laboratory, located in Oklahoma City, Oklahoma, and also by University of Florida Pathology Laboratories located in Gainesville, Florida.

The report of analysis of specimens of the pilot-rated student by the FAA was marked "Yes" to the question putrefaction. Testing for carbon monoxide and cyanide was not performed, and the results were negative for the drug screen. Unquantified amounts of N-Butanol and N-Propanol were detected in the muscle specimen, and 112 mg/dL ethanol was detected in the muscle specimen while 17 mg/dL ethanol was detected in the liver specimen. The report by University of Florida indicated the result was positive (32 mg/100g) for ethanol in the liver specimen, while the results were negative for the comprehensive drug screen. The report indicated the liver specimen was unsuitable for Carboxyhemoglobin analysis by co-oximtery, but analysis by microdiffusion indicated normal percent Carboxyhemoglobin.

The results of analysis of specimens of the flight instructor by FAA revealed testing for carbon monoxide and cyanide was not performed, and the results were negative for the drug screen. No ethanol was detected in the muscle specimen. The report by University of Florida indicated the results were negative for volatiles and the comprehensive drug screen. The report indicated the muscle specimen was unsuitable for Carboxyhemoglobin analysis by co-oximtery, but analysis by microdiffusion indicated normal percent Carboxyhemoglobin. TESTS AND RESEARCHTesting was performed using a Polk County Sheriff's Office helicopter in an effort to determine the altitude an aircraft would first come into view of the same security camera that recorded the end portion of the flight. The testing revealed that an aircraft first came into view of the camera at 145 feet above ground level; the helicopter was over the impacted building.

A performance study was performed by NTSB personnel using radar data correlated to the accident airplane. The performance study indicated that for the final 3 minutes of flight, or between 0910 and 0913, which included a right turn, the groundspeed decreased from about 121 mph to 103 mph resulting in a decrease of 5.75 mph per minute. At 0912:25, the airplane began a right turn, and between 0912:25 and 0912:58, the airplane changed heading from 172 to 239 degrees, resulting in a rate of turn of about 2 degrees per second. The final 13 data points (which included the right turn) have no altitude associated with them; therefore, the rate of descent could not be determined. The report also reviewed the video clip that captured the final portion of the descent. The five frames that recorded images of the airplane descending at a steep angle indicated that in the second frame, the fuselage of the airplane was aligned vertically and the wings were on the horizontal axis. The calculated rate of descent (estimate) was approximately 211 mph, but the report indicated that estimate was an approximation because of the distortion of the lens, the blurriness of the aircraft image, and the unknown trajectory of the aircraft. The report also indicated the estimate was higher than the final calculated groundspeed from radar by more than 100 mph.

Examination of the tubular structure and fractured left rudder cable was performed by the NTSB Materials Laboratory located in Washington, D.C. According to the NTSB Materials Laboratory Factual Report, metal loss was noted near both fracture surfaces of the tubular structure marked A and B. Areas adjacent to the fracture marked "A" showed deformation of the wall which was folded towards the forward direction, consistent with contact with another object moving forward relative to the cluster. Closer examination of the tubular structure marked "B" revealed the wall was deformed outward at the opposite edge of the area of metal loss. A crack extended from the edge of the metal loss at a location adjacent to and just below the outward deformation. Examination of the left rudder cable revealed the end did not display broomstraw or splaying, though the ends were heavily damaged by the postcrash fire, which precluded determination of the failure mode. At the other end of the cable piece, the fracture through the attachment lug showed rough features consistent with overstress fracture.

Several days after the accident, an individual who was reportedly familiar with the operator's business and maintenance practices contacted NTSB and while choosing to remain anonymous provided NTSB a document that outlined possible issues with airplanes operated by the flight school, including the accident airplane. The reported items pertaining to the accident airplane included a bird strike to the right wing root, gear collapse during ground operation, temporary loss of power from both engines during climb-out, material/debris inside the fuel tank, normal maintenance items, and recurring issues with the aircraft's brakes. No maintenance record entries could be found directly attributed to the gear collapse or engine mount; the remaining items contained corrective action in the maintenance records.