PRELIMINARY
Mosquito-abatement Flight Strikes Power Lines on Landing
Beechcraft King Air A90, Slidell, La., April 19, 2016–The aircraft struck powerline towers while attempting to land at Slidell Municipal Airport (ASD) in night VMC following a 75-minute mosquito-abatement aerial application flight. The aircraft had departed ASD at 8 p.m. On returning to land, the two-person crew radioed their intentions to fly a visual approach to Runway 18 ahead of a company aircraft practicing the published GPS approach to the same runway. The accident pilots radioed they were on left base for Runway 18 as the second aircraft crossed the final approach fix, and seconds later the pilots in the company aircraft saw an electrical arc, followed by a fire on the ground. The crew attempted to contact the accident aircraft before radioing emergency personnel.
The aircraft crashed in a marsh 0.6 nautical miles NNW of the approach end of Runway 18, killing both occupants. Investigators determined the aircraft initially struck two towers, between 70 and 80 feet high, suspending high power transmission lines 200 yards north of the main wreckage site. The airplane’s left wing tip and a portion of the application tank were found near the towers. Weather 20 minutes before the accident was reported as calm wind and clear sky, with 10 miles visibility.
FACTUAL
STC Inspection Discrepancies in Hawaii C208 Ditching
Cessna 208B Grand Caravan, near Kalaupapa, Hawaii, Dec. 11, 2013–The single-engine turboprop ditched in the ocean shortly after departing Runway 5 at Kalaupapa Airport (PHLU) in day VMC for a Part 135 flight to Honolulu. The pilot told investigators he heard a loud bang as the aircraft climbed through 500 feet agl on a left downwind departure, followed by an immediate loss of engine power and “zero” readings on all engine gauges.
The Pratt & Whitney Canada (PWC) PT6A-114A had accumulated 4,899.6 hours and 9,303 cycles since new. In July 2012, the operator received PWC and FAA approval for a 200-hour extension to the engine’s 3,600-hour TBO. Later that month, at 3,752.3 hours total time, the engine was placed on the Maintenance on Reliable Engines (More) STC, which raised the TBO to 8,000 hours in exchange for more frequent inspections under concurrent PWC and More maintenance schedules. The engine had operated under this STC for 1,137.3 hours at the time of the accident.
According to airframe and engine records, the engine received a hot-section inspection (HSI) when the More STC was issued. No evidence of compliance with a required compressor turbine (CT) blade metallurgical evaluation at the same time was found. The most recent engine inspection was performed 3.9 hours before the accident, consisting of the More STC 100-, 200- and 400-hour inspections. The 400-hour procedure included a hot-section inspection, which required scrutiny of the compressor blades with a borescope.
Investigators also noted that More STC documentation did not reference PWC service information letter (SIL) PT6A-116R3 regarding borescope examination of the trailing edges of the CT blades, and that More STC guidance conflicted with PWC requirements for engine condition trend monitoring (ECTM). The operator told investigators it found the combined guidance documentation from the More literature, PWC Maintenance Manuals and service bulletins confusing, and that its interpretation of the guidance led it to believe that additional destructive blade tests were not necessary under the extended CT blade inspection intervals allowed by the More STC.
The aircraft was recovered from the water one week after the accident. Despite extensive damage from impact and saltwater corrosion, engine components testing in January 2014 revealed that the power turbine blades were all present, but fractured, with one third to four fifths of their spans remaining and damage signatures consistent with overload separation. No evidence of fatigue cracking was found on the compressor turbine vane ring, but an inclusion was noted in one of the examined blades located away from the main fracture surface, with no adjacent cracks.
The aircraft entered the water in a wings-level, slightly nose-high attitude and remained largely intact before sinking. The pilot and eight passengers were able to exit the aircraft through its right rear door. U.S. Coast Guard and Maui Fire and Rescue helicopters recovered the pilot and passengers about 80 minutes after the ditching; the pilot and two passengers were seriously injured, and another passenger, a state health official, later died from “acute cardiac arrhythmia due to hyperventilation,” according to a medical examiner. Investigators noted that she had been wearing an infant life vest. Surviving passengers told investigators that some of them had difficulty properly inflating and wearing their life vests after the ditching, and that the pilot had not conducted a preflight safety briefing that would have included guidance on the locations and operation of the life vests.
Pilot in NM Medevac Fatal Had Worked Eight Consecutive Shifts
AgustaWestland A109E, near Newkirk, N.M., July 17, 2014–The pilot of a TriState Careflight (TSCF) medevac helicopter that crashed in remote terrain in probable night IMC had been on call for 15 days, twice the typical company schedule, with a single 24-hour off-duty period within that time, according to an updated factual report from the NTSB. The accident occurred during the pilot’s eighth consecutive on-call shift.
The accident flight departed Santa Fe Municipal Airport (KSAF) at 12:51 a.m. on a company VFR flight plan for the Part 91 repositioning flight to a hospital in Tucumcari, N.M. His resumé and company records showed that the 46-year-old commercial pilot had accumulated 6,167 total hours, with 208 hours in type, more than 410 hours of night time, 75 hours of simulated instrument conditions and zero hours of actual instrument conditions. The pilot had regularly flown over desert terrain in New Mexico, Arizona and Nevada since being hired by the company in 2009, and had operated from the Santa Fe base for 1.5 years with numerous flights in the Santa Fe and Tucumcari areas.
The accident site was within a region known by TSCF crews to experience low-visibility conditions frequently. The National Weather Service Surface Analysis Chart for midnight MDT noted a surface trough over the accident site, a stationary front south of the accident site, and three areas of low pressure to the distant northwest, south and southeast of the accident site. Clouds and precipitation were possible throughout this area, and the NWS Storm Prediction Center had forecast a 15-percent chance of damaging wind with gusts of 50 knots in thunderstorms within the vicinity of the accident site until 6 a.m. on July 17.
Satellite tracking data and information from onboard GPS showed that the helicopter flew eastbound from SAF at 6,600 feet msl (1,200 to 1,800 feet agl) with a groundspeed of about 130 knots before turning right on a SSE course toward Tucumcari, at which time it descended to 6,000 feet msl. Immediately before the accident, the helicopter turned SSW and climbed to 7,763 feet msl, before veering left and entering a descending left 360 that tightened as the turn progressed. The last GPS reporting point showed the helicopter at 4,840 feet msl (200 feet agl) with an estimated final descent rate exceeding 14,000 fpm. The three crewmembers perished.
The NTSB noted that the pilot had accrued at least 162 hours flying with night-vision goggles (NVG). While company procedures required flight crews to use NVGs in low visibility, impact damage prevented positive determination of whether the devices were in use at the time of the crash.
FINAL
NTSB: Fast Touchdown Led to SMO Runway Excursion
Cessna 525A CJ2, Santa Monica, Calif., Sept. 29, 2013–A fast landing approach speed, and the pilot’s failure to maintain directional control on the landing rollout, led to a highly publicized fatal runway excursion accident at California’s Santa Monica Municipal Airport (SMO) that claimed the lives of the four people on board, according to the NTSB.
The Part 91 flight departed Friedman Memorial Airport (SUN) in Hailey, Idaho, at 4:14 p.m. PDT bound for SMO on an IFR flight plan in daytime VMC. Witnesses told the NTSB the aircraft made a seemingly normal approach to land on Runway 21 before it started drifting to the right side of the runway during rollout. The nose pitched up suddenly, then dropped back down before the aircraft departed the runway surface. No abnormal communications were received from the aircraft, which was based at SMO.
At 6:24 p.m. the field’s AWOS reported wind from 240 degrees at 4 knots, visibility 10 statute miles with clear sky, temperature 21 degrees C and dew point 12 degrees C, and altimeter 29.97 in Hg. Investigators determined the sun’s angle was near horizon level at the time of the accident, oriented 54 degrees right of the Runway 21 centerline.
Field security cameras first recorded the aircraft on the ground approximately 2,000 feet from the Runway 21 approach threshold. The jet passed midfield without noticeable deceleration before it departed the runway, hit the 1,000-foot remaining distance marker along the side of the runway, and struck a row of hangars, collapsing the roof on one and resulting in a fire.
Estimated groundspeed derived from the recordings was 82.5 knots on touchdown, 10 knots faster than an optimal CJ2 arrival flown by Cessna pilots touching down 1,000 feet from the runway’s approach threshold. Additional video recordings helped investigators determine an average rollout speed of 75 knots before impact.
The first evidence of braking was a light tire mark “scuff” about 2,800 feet from the threshold of Runway 21 and 35 feet right of the centerline. These markings became heavy and dark, consistent with increased braking effort, along the path of the aircraft’s departure from the runway surface.
Maintenance records indicated the CJ2 had last been inspected on Sept. 7, 2013, and no mechanical anomalies were noted in the engines, flight controls or braking systems. The NTSB could not determine from video footage whether the flaps were deployed on landing, or if they had been moved immediately on touchdown to the “ground flap” position (60-degree deployment) for maximum braking effectiveness. However, the flaps were in the ground flap position by the time the aircraft struck the hangar.
In-flight footage recorded by passenger PEDs showed several unrestrained pets, including a large dog, on board with unfettered access to the cockpit. However, investigators could not determine if the animals caused a distraction, or related event, in the accident sequence. The aircraft was not equipped with a flight data recorder or a cockpit voice recorder.
Blown Tire Led to Hydraulic Malfunction in Hawker Gear-Up Landing
Raytheon Hawker 800XP, near Denver, Colo., Oct. 15, 2014–The Part 91 repositioning flight originated from Centennial Airport (APA) in Englewood, Colo., operating in day VMC under an IFR flight plan en route to Arnold Palmer Regional Airport (LBE) in Latrobe, Penn. The pilots opted to continue their takeoff roll and depart APA after the pilot flying felt and heard a vibration in the airframe. After departure, personnel in the control tower told the crew they had momentarily seen white smoke from the jet, and the aircraft’s hydraulic low-pressure lights illuminated. The pilots opted to divert to the longer runways at Denver International Airport (DEN) after they were unable to lower the landing gear. The aircraft then landed with flaps and gear retracted on Runway 34L (16,000 feet by 200 feet) at DEN, with no injuries to the two pilots and one other crewmember on board.
Investigators found the inboard tire on the Hawker’s left main gear assembly had ruptured, and separation damage to the hydraulic servo block on the landing gear extend/retract actuator that appeared to have been caused by impact forces from parts of the blown tire. The NTSB noted this damage was consistent with an August 1999 incident involving a Hawker 600A, adding that a subsequent service bulletin had called for replacement of the main landing gear jack during the 5,000-cycle overhaul with a landing gear jack with improved servo block mounting hardware, for better resistance to tire debris. The accident aircraft had accumulated 2,199 cycles at the time of the accident and had not had this upgraded component installed.
As a result of this accident, the FAA issued Special Airworthiness Information Bulletin NM-15-24 alerting Hawker owners, operators and maintenance technicians to the potential for damage to the servo block by debris from tire tread separation during takeoff. The agency recommended that affected aircraft have these components replaced as per the procedures outlined in Raytheon Aircraft Bulletin 32-3777, dated October 2006.
Investigators discovered no apparent manufacturing anomalies or signs of cuts or foreign object debris (FOD) damage on the ruptured tire. Thermal damage to the tire’s inner layers appeared consistent with possible over-deflection associated with low tire pressure, and/or if the tire had been overloaded. The operator stated that crews checked tire pressures before each flight, but the pressures were not recorded. Investigators could not determine if the tire had been consistently operated below the recommended pressure.