Aviation Accident Summaries

Aviation Accident Summary MIA02FA084

Carolina, PR, USA

Aircraft #1

N45BS

Mitsubishi MU-2B-35

Analysis

The flight departed VFR, and when near the destination airport, was advised by air traffic control to hold VFR over the "plaza" and to make left 360 degree orbits. Several witnesses reported light rain was occurring at the time of the accident; there was no lightning or thunder. One witness located where the airplane came to rest reported observing the airplane emerge from the base of the clouds in a 45-degree left wing low and 20 degrees nose low attitude. He momentarily lost sight of the airplane but then noted it rolled to a wings level attitude. He also reported hearing the engine(s) "cutting in an out." Another witness located approximately 1/4 mile north of the accident site observed the airplane flying eastbound beneath the clouds in a right wing and nose low attitude, he also reported hearing the engine(s) sounding like they were "cutting in and out." A pilot-rated witness located an estimated 1,000 feet from where the airplane came to rest estimated that the ceiling was at 300 feet and there was light drizzle. He observed the airplane in a 45-degree angle of bank to the right and in a slight nose low attitude. He stated that the airplane continued in that attitude before he lost sight of the airplane at 250 feet. The airplane impacted trees then a concrete wall while in a nose and right wing low attitude. The airplane then traveled through automobile hoists/lifts which were coverered by corrugated metal, and came to rest adjacent to a building of an automobile facility. Impact and a postcrash fire destroyed the airplane, along with a building and several vehicles parked at the facility. Examination of the airplane revealed the flaps were symmetrically retracted and landing gears were retracted. No evidence of preimpact failure or malfunction was noted to the flight controls. Examination of the engines revealed no evidence of preimpact failure or malfunction; impact and fire damage precluded testing of several engine accessories from both engines. Examination of the propellers revealed no evidence of preimpact failure or malfunction. Parallel slash marks were noted in several of the corrugated metal panels that covered the hoists/lifts, the slashes were noted 25 and 21 inches between them. According to the airplane manufacturer, the 25 inch distance between the propeller slashes corresponds to an airspeed of 123 knots. Additionally, the power-off stall speed at the airplanes calculated weight with the flaps retracted and 48 degree angle of bank was calculated to be 122 knots. Review of NTSB plotted radar data revealed that the pilot performed one 360-degree orbit to the left with varying angles of left bank and while flying initially at 1,300 feet, climbing to near 1,500 feet, then descending to approximately 800 feet. The airplane continued in the left turn and between 1502:10 and 1502:27, the calibrated airspeed decreased from 160 to 100 knots. At 1502:27, the bank angle was 48 degrees, and the angle of attack was 26 degrees. Between 1502:30 and 1502:35, the true heading changed indicating a bank to the right. The last plotted altitude was 200 feet, which occurred at 1502:35. A NTSB weather study indicated that at the area and altitude the airplane was operating, NWS VIP level 1 to 2 echoes (light to moderate intensity) were noted. Additionally, the terminal aerodrome forecast (TAF) for the destination airport indicated that temporarily between 1400 and 1800 (the flight departed at approximately 1436 and the accident occurred at approximately 1503), visibility 5 miles with moderate rain showers, scattered clouds at 1,500 feet, and a broken ceiling at 3,000 feet.

Factual Information

HISTORY OF FLIGHT On April 15, 2002, about 1503 Atlantic standard time, a Mitsubishi MU-2B-35, N45BS, registered to Maxfly Aviation, Inc., operated by Crucian International Airlines, experienced a loss of control while orbiting and crashed at an automobile parts and service facility near Carolina, Puerto Rico. Instrument meteorological conditions prevailed in the area at the time of the accident and no flight plan was filed for the 14 CFR Part 91 positioning flight from Henry E. Rohlsen Airport (TISX), St. Croix, U.S.V.I., to Luis Munoz Marin International Airport (TJSJ), San Juan, Puerto Rico. The airplane was destroyed by impact and a post crash fire and the airline transport-rated pilot, the sole occupant, was fatally injured. One individual on the ground at the automobile facility was fatally injured and two individuals at the facility sustained minor injuries. The flight originated from St. Croix, about 1436. On the day of the accident at 1345, the pilot phoned the San Juan Automated Flight Service Station (SJU AFSS), and filed two flight plans, neither of which involve the accident flight. The pilot did not obtain a preflight weather briefing during the phone call. According to a transcription of communications with the San Juan Combined En Route Approach Control facility, at 1437:47, the pilot contacted the facility and advised that the flight had departed from TISX, climbing through 2,500 to 8,500 en route to TJSJ. The pilot was provided a discrete transponder code and the flight was radar identified. The flight continued and at 1454:07, air traffic control communications were transferred to San Juan Approach Control. The pilot established initial contact with that facility and advised the controller that the flight was, "...out a eight point five." The controller acknowledged and provided an altimeter setting, which the pilot acknowledged. At 1459:16, the controller advised the pilot, "...hold [visual flight rules] over plaza please make left [360's]." The pilot responded with the last two letters of the call sign of the airplane and at 1502:31, the controller advised the pilot to hold south of Plaza Carolina, to continue south and hold south of the plaza. There was no response from the pilot. At 1505:02, the controller advised on the frequency that the airplane was lost from radar. Several witnesses reported that the weather conditions near the crash site at the time of the accident consisted of light rain; there was no lightning or thunder. One witness located where the airplane came to rest reported observing the airplane emerge from the base of the clouds in a 45-degree left wing low and 20 degrees nose low attitude. He momentarily lost sight of the airplane but then noted it rolled to a wings level attitude. He also reported hearing the engine(s) "cutting in an out." Another witness located approximately 1/4 mile north of the accident site observed the airplane flying eastbound beneath the clouds in a right wing and nose low attitude, he also reported hearing the engine(s) sounding like they were "cutting in and out." A pilot-rated witness located an estimated 1,000 feet from where the airplane came to rest estimated that the ceiling was at 300 feet and there was light drizzle. He observed the airplane in a 45-degree angle of bank to the right and in a slight nose low attitude. He stated that the airplane continued in that attitude before he lost sight of the airplane at 250 feet. The pilot-rated individual did not witness the accident but traveled to the accident site and observed a postcrash fire. PERSONNEL INFORMATION The pilot was the holder of an airline transport pilot certificate with ratings airplane multi-engine land and sea. He was also the holder of a commercial pilot certificate with the rating airplane single engine land. He was issued a first class medical certificate on January 3, 2002, with the limitation, "Holder shall carry glasses for near vision while exercising the privileges of his airman certificate." His last check ride in accordance with 14 CFR Part 135.297 occurred on February 15, 2002, during a 1.5 hour flight in the accident airplane. The result was listed as "approved." Review of his pilot logbook that begins with an entry dated January 2, 1994, and ends with an entry dated April 8, 2002, revealed he logged a total time of approximately 768 hours in Mitsubishi model MU2 airplanes. Further review of his pilot logbook revealed that between January 28, 2000, and April 8, 2002 (the last logged entry), he logged a total time of 586.3 hours all in the accident airplane. Between January 4, 2002, and April 8, 2002 (the last logged entry), he logged a total time of 117.1 hours; all in the accident airplane. He logged a total time of 10,583.2 hours, of which approximately 9,413 hours were as pilot-in-command. His total logged time for multi-engine land and sea was approximately 10,243 hours. AIRCRAFT INFORMATION The airplane received type certification on May 28, 1971, and was manufactured in 1972, as a Mitsubishi MU-2B-35, serial number 558. The airplane was initially certified and equipped with two Air Research TPE-331-6-251M engines rated at 665 shaft horsepower. The engines were modified in accordance with Service Bulletin TPE331-72-0120, which changed the engine model to TPE331-6-252M; the shaft horsepower remained unchanged. The airplane was also equipped with two hydraulically operated Hartzell model HC-B3TN-5C constant speed propellers which are full manual feathering and reversing. The airplane was last inspected on February 13, 2002, in accordance with a 50/150 hour inspection using the airline's maintenance manual and checklist. The airplane had accumulated approximately 60 flight hours since the inspection as of the last logged flight in the pilot's pilot logbook (April 8, 2002). Review of the airplane maintenance records revealed that the last recorded altimeter system and transponder checks performed in accordance with Title 14 Code of Federal Regulations (CFR) Part 43, Appendix's E and F, occurred on January 22, 1999. A computerized printout for the airplane dated July 10, 2001, indicates that the "static", "[altimeter]" and "transponder" checks due every 24 months, were due on January 1, 2003. A review of the aircraft log sheets revealed that between January 16, 2002, and April 5, 2002, the airplane had been operated 71.6 hours on 95 flights; there were only two pilot-reported discrepancies recorded in the log between these dates. Both discrepancies were related to the right engine and were corrected. The first dealt with the starter/generator, and the second dealt with the bleed valve. METEOROLOGICAL INFORMATION According to an NTSB Meteorological Factual Report (NTSB Weather Report), a special weather observation taken at the Luis Munoz Marin International Airport, San Juan, Puerto Rico, at 1456 (approximately 7 minutes before the accident), indicates the wind was from 080 degrees at 9 knots, the visibility was 10 statute miles, scattered clouds existed at 900 feet, a broken ceiling existed at 2,100 feet, overcast clouds existed at 4,500 feet, the temperature and dew point were 24 and 23 degrees Celsius, respectively, and the altimeter setting was 30.01 inHg. The remarks section indicates the rain ended at 1444, the sea level pressure was 1016.1 mb, and rain showers were noted in the vicinity southeast through south and north through northeast. Another special weather observation taken from the same airport at 1511 (approximately 8 minutes after the accident), indicates the wind was from 070 degrees at 12 knots gusting to 17 knots, the visibility was 10 statute miles, a broken ceiling existed at 800 feet, a second broken layer existed at 1,200 feet, overcast clouds existed at 3,500 feet, the temperature, dew point and altimeter remained the same from the previous special observation. The NTSB Weather Report further indicated that doppler weather radar indicated that at 1508 in the area and altitude the airplane was flying, a band of echoes with reflectivities in the range of 15 to 35 dBZ or NWS VIP Level 1 to 2 (very light to light to moderate) intensities were noted over the accident site. The Geostationary Operations Environmental Satellite number 8 (GOES-8) data infrared and visible imagery indicated no significant convective activity depicted along the route from the Virgin Islands to Puerto Rico; and none in the general vicinity of the accident site. A large band of low and middle altitude clouds cover the area and obscures the accident site. The Area Forecast (FA) for the San Juan Flight Information Region (FIR) issued at 1115 on April 15, 2002, valid from 1400Z through 0200 on April 16, 2002, for the San Juan FIR south of 20 degrees North latitude was for scattered clouds at 2,500 feet, scattered to broken clouds at 5,000 feet, with layered clouds tops above 24,000 feet. Widely scattered rain showers and occasional broken ceilings at 2,500 feet through 2200 were forecast. The Luis Munoz Marin International Airport (TJSJ) Terminal Aerodrome Forecast (TAF) issued on the day of the accident at 1330 (approximately 15 minutes before the pilot phoned the SJU AFSS and 1 hour 46 minutes before the flight departed), valid from 1400, to 1400 the following day indicates in part that beginning at 1400 (approximately 36 minutes before the flight departed), the wind from 080 degrees at 15 knots gusting to 20 knots, visibility greater than 6 miles, a few clouds at 1,500 feet, ceiling broken at 3,500 feet, overcast clouds at 7,000 feet. Temporary condition between 1400 and 1800, wind from 080 degrees at 15 knots gusting to 25 knots, visibility 5 miles in moderate rain showers, scattered clouds at 1,500 feet, ceiling broken at 3,000 feet, overcast clouds at 7,000 feet. COMMUNICATIONS The pilot was last in contact with the San Juan Combined En Route Approach Control facility (CERAP). The controller who was moderately busy working combined East and West positions reported marginal VFR conditions existed at TJSJ. WRECKAGE AND IMPACT INFORMATION Examination of the accident site area revealed damage to a palm tree approximately 40 feet above ground level; the palm tree was located near a residence. Additional damage to another tree located 17 feet from the palm tree was noted. An approximately 10-feet high concrete block wall oriented east/west located approximately 15 feet past the second tree was damaged; the outer right wing panel was lodged in the broken wall section. The straight line magnetic heading from the damaged palm tree to the damaged concrete block wall was approximately 096 degrees. the right fuel tip tank was located on the north side of the wall, adjacent to it. A smell of jet fuel was noted in the area where the right tip tank was found. Automobile bays covered by corrugated metal panels were located on the south side of the concrete wall; some of the bays contained automobile lifts/hoists associated with the automobile service facility. Parallel slashes measuring 21 and 25 inches between the two were noted in several of the panels, respectively. The airplane came to rest upright on a magnetic heading of approximately 160 degrees, adjacent to a building of the automobile facility. The center of the fuselage was located 50 feet from the damaged concrete wall section, and approximately 82 feet from the first damaged tree. The aft section of the left fuel tip tank was found in one of the rooms of the second floor of the building. Fire and impact damage was noted to the building. A total of seven cars were damaged; two of which were destroyed by the postcrash fire. Examination of the airplane revealed the wing box section and the outer sections of both wings were separated; sections of both wings were located in the main wreckage area. Both engines remained secured to wing structure; however, both engines/wing structure were separated. The left horizontal stabilizer and elevator remained attached, while only 1/3 span of the right horizontal stabilizer and elevator remained attached. The outboard tip of the right elevator was found adjacent to the main wreckage. A semi-circular indentation was noted on the leading edge of the right horizontal stabilizer near the fracture surface. The vertical stabilizer and rudder remained attached. Both main fuel shutoff valves were in the open position; slight debris was noted in the left valve. Both propellers were separated from the engines and were found in close proximity to the main wreckage area. The left propeller by serial number was noted to have all three propeller blades secured by clamps, while the right propeller by serial number was noted to have two of the three propeller blades secured by clamps. The remaining blade of the right propeller was separated but found in close proximity to the main wreckage. The cockpit was impact and fire damaged and the cabin interior was consumed by the post crash fire. Both elevator trim tab actuators were symmetrically extended 1 7/8 inches which corresponds to 15 degrees nose up. The rudder trim actuator measured 7.0 inches extended with equates to a neutral position. The left and right aileron trim tab actuators measured 2.625 and 3.00 inches extended respectively, which equates to neutral and 1 degree, respectively. The inboard, main, and outboard left and right flap actuators were all retracted, as were all landing gear actuators. Continuity of both elevator flight control cables was confirmed from the front to rear bellcranks, and both rudder flight control cables were continuous from the rear bellcrank to approximately 6 feet forward of the main landing gear location where both cables exhibited evidence of tension overload. Both spoiler flight control cables were connected at the spoiler mixer; one cable exhibited tension overload approximately 12 feet from the spoiler mixer while the second cable was pinched in the wreckage and molten aluminum. Both cables were cut approximately 6 feet forward of the main landing gear location. The roll, pitch, and yaw autopilot servos were all free to rotate; the roll servo capstain was separated from the control head. Both engines and propellers were recovered for further examination. Examination of the left engine was performed at the manufacturer's facility with NTSB oversight. Impact and heat damage was noted externally. The examination revealed the propeller shaft rotated freely in the nose cone housing, the propeller mount flange was bent aft. The hub and ring gears inside the nose cone housing appeared undamaged. The mounting studs of the planetary gears were bent in the direction of engine rotation. Binding preventing 360 degrees of rotation was noted to several of the gears, propeller governor drive gearshaft, and high speed pinion of the intermediate gearbox (diaphragm) assembly. The gears of the planet gear assembly were noted to rotate freely; no evidence of preimpact failure or malfunction was noted to the intermediate gearbox assembly. The accessory drive housing (gearcase) assembly, torque sensor system and direct drive fuel control (DDFC) gears did not exhibit evidence of preimpact failure or malfunction. The shouldered (main) shaft was not fractured while the torsion shaft was fractured approximately 1 inch forward of the aft end; the fracture surface was consistent with shear. The first stage compressor shroud exhibited approximately 180 degrees of rotational scoring, and the leading edges of 7 of blades of the first stage compressor impeller were bent opposite the direction of rotation. The aft impeller hub of the first stage impeller exhibited 360 degrees of rotational scoring, with corresponding rotational scoring noted on the first stage compressor diffuser assembly air seal area. The aft flange of the second stage compressor shroud housing was fractured nearly 360 degrees; 360 degrees of rotational scoring was noted on the second stage compressor shroud surface. Rotational scoring on the shroud line edges of all blades of the second stage impeller was noted. The forward bolt flange of the combustor plenum was buckled and a 1-inch fracture in the case was noted; no burn through was noted. The leading and trailing edges of al

Probable Cause and Findings

The failure of the pilot to maintain airspeed (Vs) while maneuvering following inadvertent encounter with clouds resulting in an inadvertent stall and uncontrolled descent and subsequent in-flight collision with trees, a wall, and a building.

 

Source: NTSB Aviation Accident Database

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