Aircraft Accident/Incident Report

San Jose Del Colombia
Monday, July 27, 1998 14:05 CDT

HISTORY OF FLIGHT On July 27, 1998 about 1405 atlantic standard time an Ayres S2R-T34, N3090M, lost control in-flight and collided inverted with the ground in San Jose Del Guavare, Colombia. The airplane was owned by the United States Department of State and operated by DynCorp Aerospace Technology under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed for the local training flight. The flight instructor (first pilot) and second pilot sustained fatal injuries, and the airplane was destroyed by impact forces with the ground and subsequent post-crash fire. The flight had originated from the San Jose airport about 1300. According to witnesses, the first pilot was preparing a second pilot for his instructor check ride. The airplane had departed about 1300, and at 1400-contacted San Jose airport (call sign Tango Base). The first pilot stated that it was raining at their location, which was unknown by the witnesses, and that they were heading for the practice area. The instructor stated that he would keep them posted of the flights progress. That was the last radio contact with the airplane. The airplane was not reported missing until 1630, when someone on the field inquired about its location. Search efforts began about 1720 and the airplane was located the next day at 0555. Rescuers stated that they interviewed ground witnesses in an attempt to locate the aircraft. The rescuers stated that the witnesses observed the airplane doing what they called "acrobatic movements" and the airplane began to fall. One individual being questioned moved his hand as if to make a fluttering movement as that of a leaf falling. He then said that the plane nosed dived and he heard a "Krumpfh" as it impacted the ground. Another local resident stated that they observed the airplane falling rearward and then nose dive into the ground. Another resident also stated that they observed the airplane doing "acrobatic maneuvers" and saw smoke come from the engine. The aircraft began a climb, stalled, and the engine stopped and it began to flutter as previously described towards earth. As the aircraft fell the engine restarted, however, it was too late, and again a large "Krumph" was heard upon impact. PERSONNEL INFORMATION The first pilot was certificated as a commercial pilot with instrument and multiengine ratings and flight instructor ratings. The pilot reported having 9000 civilian hours on his last medical examination. The pilot's most recent second class medical was issued on September 5, 1997. Additional pilot information may be obtained in this report on page 2 and 3 under the section titled Owner/Operator and first pilot information. The second pilot was certificated as an airline transport pilot with multiengine land ratings. Additionally, the pilot had a commercial rating in single engine land, helicopters and glider, and was a certificated flight instructor. The pilot reported having 18000 civilian hours on his last medical examination. The pilot's most recent second class medical was issued on May 22, 1998. Additional second-pilot information may be obtained from Supplement E, of this report entitled second-pilot information. AIRCRAFT INFORMATION The Ayres S2R-T34 was a two seat, all metal, low wing, turboprop, and agricultural monoplane. The accident airplane had been modified and was for the purpose of this report a model S2R-T65. (See attachment for flight manual). Weight and balance calculations were provided by the Ayres Corporation, which resulted in a gross weight of 8,590 pounds and a center of gravity (CG) of 29.297, both were within the operating waiver limits at the time of the accident. (See Attachment). In a bulletin issued by Dyncorp, on August 19, 1996, an operating waiver was issued for the T-65 Aircraft which increased the Maximum gross weight for take off by a factor of 1.2 and expanded the center of gravity limitations by a factor of 1.2. (See Attached bulletin). METEOROLOGICAL INFORMATION According to witnesses, visual meteorological conditions prevailed at the time of the accident. Witnesses stated that prior to the accident it had been raining, however that had passed. There was no weather reporting facility in the area. Additional meteorological information may be obtained in this report on page 4, under the section titled Weather Information. WRECKAGE AND IMPACT INFORMATION The aircraft was found inverted partially imbedded in soft ground at Global Positioning System Coordinates: Latitude N 02 35' 50" Longitude W 072 51' 18". The aircraft remained together with the exception of the engine, which had separated from the aircraft but was co-located with the wreckage. The fuselage exhibited accordion-type crushing along its longitudinal axis, and the roll cage was crushed and deformed. The two pilot seats, seat backs were fractured. The top fuselage longeron was fractured forward of the aft seat position. The elevator control tube assembly was deformed but remained attached to the aft pilot's control stick. Control continuity was not established between the aft and front pilot's control stick because the interconnect torque tube was melted by the post-crash fire. The forward pilot's control stick was fractured at the base and the torque tube could not be located. The fuel header tank was melted. The rudder cables remained attached to the rudder assembly, and one cable remained attached to the rudder pedal attach bracket. The other cable attach assembly had melted in the post-crash fire and the cable was detached. Both cables were uncompromised through their full length. The emergency locator transmitter was missing from its mounting bracket and was not recovered. The rudder and vertical stabilizer exhibited severe top-down accordion-like crushing, and had folded over towards the right horizontal stabilizer and remained attached to the fuselage. The rudder and elevator were not free to move. The horizontal stabilizer support bars exhibited bending consistent with compression. The elevator trim-tabs were displaced as follows: The left elevator trim was displaced down 1 5/8 inches, and the right tab was displaced down 1 3/8 inches. Control continuity was established from the elevator to the aft pilot's control stick. The tail wheel and spindle remained attached to the fuselage and created a deformation on the bottom of the fuselage directly above the attach point. The wing sections and wing box were found detached from the fuselage. The right rear wing attach fittings were torn loose from the fuselage attach point. The fuel cells were ruptured and one was located approximately 5 meters away from the wreckage. It could not be determined if the fuel cell had been moved when the wreckage was disturbed by unknown person(s) prior to the examination and recovery. The ailerons and flaps remained attached to the wings. The aileron push-pull tubes remained intact and were melted at the fuselage attach points. Aileron and flap control continuity was established to the cockpit area. The forward cockpit controls and switches were found in the following positions: Propeller - Feather; Throttle - Beta; Fuel condition lever - cutoff; Generator switch - off; Battery - on; Starter - on; Trim tab - nose-up. The aft cockpit controls were found in the following position: Propeller - feather; Throttle - Closed; Fuel condition lever - cutoff; Trim Tab - nose-up. Examination of the propeller on-scene found one blade separated from the hub and stuck in the ground where the aircraft came to rest. The remaining blades remained attached and were in various stages of bending. (See Attached Photographs). The engine had separated from the airframe with impact damage noted on all sides, including structural separation of the reduction gearbox forward housing. The engine was stripped of all airframe-related debris, with the exception of the airframe engine driven boost pump, and shipped to Pratt & Whitney Canada Inc. Longueuil, Quebec, Canada for further examination. The propeller governor, oil to fuel heater, high-pressure fuel pump, and fuel control unit was examined on-scene and sent with the engine for further examination. MEDICAL AND PATHOLOGICAL INFORMATION On August 6, 1998, a toxicology examination of the first pilot was conducted by the FAA Toxicology Research Laboratory. The examination revealed no ethanol detected in the urine. Tests for carbon monoxide and cyanide were not performed due lack of suitable specimen. Desalkylflurazepam was detected at 194 (ug/ml, ug/g), Acetaminophen was detected in the Urine, and 0.171 (ug/ml, ug/g) desalkylflurazepam was detected in the Liver. On August 6, 1998, a toxicology examination of the second pilot was conducted by the FAA Toxicology Research Laboratory. The examination revealed 93 (mg/dl, mg/hg) Ethanol detected in Muscle, 101 (mg/dl, mg/hg) Ethanol detected in Lung Fluid, 10 (mg/dl, mg/hg) Ethanol detected in Urine, 4 (mg/dl, mg/hg) N-Propanol detected in Lung Fluid, 25 (mg/dl, mg/hg) N-Propanol detected in Muscle, 5 (mg/dl, mg/hg) Acetaldehyde detected in Muscle, 3 (mg/dl, mg/hg) Acetaldehyde detected in Urine, and 12 (mg/dl, mg/hg) Acetaldehyde detected in Lung Fluid. Tests for Carbon Monoxide and Cyanide were not performed due to lack of suitable specimen. It was noted on the report that the ethanol found in this case was most likely from postmortem ethanol. TEST AND RESEARCH An engine tear-down was performed on November 17, 18, 1998 at the Pratt & Whitney Canada Service Investigation Facilities at St. Hubert, Quebec, Canada. Present were representatives from the NTSB, FAA, DynCorp Aerospace Technology, Ayres Corporation, and Pratt & Whitney of Canada. The engine was a PT6A-65AG, S/N 32624. The total numbers of hours on the engine since new was 580 with 385 cycles. The engine had been installed on the accident aircraft about 10 hours previous to the accident flight. Previously the engine had been repaired at Pratt & Whitney West Virginia under W/O 4970208 for an over-torque event. There was no other unusual maintenance reported for the engine. Initial examination of the engine found severe impact damage including complete structural separation of the reduction gearbox forward housing. The engine was received stripped of all airframe related debris, with the exception of the airframe engine driven boost pump. The propeller governor, oil to fuel heater, high pressure fuel pump, and fuel control unit were received separately. The remaining engine related controls and accessories were in place with impact damage. The engine related controls and accessories were removed as required and transferred to the P&WC Controls and Accessories Facility for separate evaluation. According to P&WC the engine power section internal components displayed light rotational signatures characteristic of the power section operating at a relatively low rate of rotation, with the propeller at a nearly feathered position, at impact. The gas generator section internal components displayed rotational signatures characteristic of the gas generator section operating at a low power level, or flamed out and spooling down from high power, at the time of impact. The frictional heat discoloration and bronze bearing material smearing of the three 1st stage planet gears is indicative of a reduction or interruption of oil flow to the bearings prior to impact. Examination of the engine oil system revealed no pre-impact conditions that would have resulted in a loss of oil pressure or interruption of oil flow to the 1st stage planet gears. There were no indications of any anomalies or distress to the engine that would have precluded normal operation prior to impact. (See attached P&WC tear-down report). Examination of the engine controls and accessories found them all to be impact damaged which precluded functional testing. However, disassembly of these units revealed no anomalies affecting normal operation that was not attributable to impact damage. ADDITIONAL INFORMATION Following the on-scene phase of the investigation 5 mechanics were interviewed who were involve with the installation of the engine on July 19, 1998, or the pre-flight inspection of the airplane just prior to the accident flight. According to the mechanics that installed the engine, there were no discrepancies noted before, during or after the installation. The engine was serviced and oil was added during, and following the engines initial run-up. However, what was discovered was that a Quality Control (QC) Inspector, in this case, helped install the engine, and then, signed off the work as the QC Inspector. According to Dyncorp Management this was not an acceptable procedure. Additionally, it was found that on July 21, 1998, two days following the installation of the engine. The same QC Inspector signed off as having completed a Phase-one inspection (PPM). It was found during the interviews that the QC Inspector did not complete all of the inspection items as he indicated on the inspection form. Again, Dyncorp Management was unaware of this occurrence and stated that this was not an acceptable procedure. (See attached interview summary's and attached PPM Inspection sheet). During the course of the investigation it was found that certain operating procedures i.e., flight planing, flight following, and radio communications were not followed associated with the accident flight. The flight crew did not file a flight plan with either the Colombian Base Commander nor Flight Operations, and flight following was not performed according the Dyncorp Management. As a result, no one on the base knew when the aircraft left, where it was going, or when it was expected to return. In addition, no one was monitoring the radios. As a result, when the aircraft was finally missed. Search and Rescue personnel didn't know where to look for the downed aircraft. (See attached Memo and Statement).

Not Yet Reported