The following information provides an awareness of problems in the hope that they can be avoided in the future. The information is based on final reports by official investigative authorities on aircraft accidents and incidents.
Crew Misidentified Intersection
Boeing 777-200. No damage. No injuries.
As the copilot, the pilot flying, lined up the 777 for takeoff from St. Kitts, West Indies, the evening of Sept. 26, 2009, the commander remarked that the runway looked very short. However, neither pilot realized that they had taxied onto the runway from an unauthorized midfield intersection, rather than from the intersection farther down the runway from which they had based their performance calculations.
At least two people recognized the error, but neither was able to bring it to the flight crew’s attention in time. The airport traffic controller, a trainee, radioed a suggestive but ambiguous query, then apparently dismissed a telltale error in the commander’s response and cleared the crew for takeoff. About the same time, the airline’s station engineer, who was among the passengers, rushed forward and told the cabin manager that he needed to warn the pilots. He took a seat, however, when the sound of increasing thrust indicated that the flight crew already had begun the takeoff.
The commander’s perception of scant runway ahead had prompted him to advise the copilot to increase power to 55 percent N1 (engine fan speed) before releasing the wheel brakes. Witnesses estimated that the 777’s main landing gear lifted off the runway about 305 m (1,000 ft) from the end of the paved surface. Recorded flight data showed that the aircraft passed 80 ft over the end of the runway. The flight was continued to the scheduled destination, Antigua, without further incident.
The aircraft was registered in England, and the Eastern Caribbean Civil Aviation Authority delegated the incident investigation to the U.K. Air Accidents Investigation Branch (AAIB).
The AAIB’s final report noted that the incident occurred during the flight crew’s first flight at St. Kitts’ Robert L. Bradshaw International Airport, which has a single asphalt runway that is 2,316 m (7,598 ft) in length and 45 m (148 ft) wide. The weather was clear, with surface winds from 090 degrees at 10 kt, and the crew planned to depart from Runway 07.
Taxiway Alpha leads southwest from the airport terminal and ends at Intersection Alpha, which is about 400 m (1,312 ft) from the approach threshold of Runway 07. The pilots reviewed performance data for takeoff using the full runway length, as well as using the 1,915 m (6,286 ft) of runway available from Intersection Alpha. “Once the speed and thrust settings were calculated, the crew agreed that the takeoff performance was satisfactory from Intersection Alpha and that this was considered preferable to backtracking on the runway for a full-length departure,” the report said.
The copilot briefed the departure but not the taxi route before the engines were started. The controller-trainee cleared the crew to taxi via Taxiway Alpha and backtrack on Runway 07. When the crew requested clearance to depart from Intersection Alpha, the trainee replied, “Roger, line up for departure.”
There were no taxiway markings or signs to guide the crew from the ramp. As the copilot turned the aircraft away from the terminal, “he identified a taxiway centerline at the rear of the ramp and assumed it to be Taxiway Alpha,” the report said. The centerline, however, was for a taxiway leading to Intersection Bravo, from which 1,220 m (4,003 ft) of runway is available for takeoff — about 695 m (2,280 ft) less than from Intersection Alpha. Departures from Bravo were not authorized by the airline.
As the copilot taxied out, the commander was head-down, completing the “Before Takeoff” checklist. “By the time he looked up and orientated himself, the aircraft was approaching [Bravo],” the report said.
The trainee and his supervisor assumed that the crew would turn west and backtrack on the runway. When they saw the aircraft turn east, the supervisor told the trainee to query the crew. “Do you not request, er, backtrack runway zero seven?” the trainee asked.
The commander replied, “Negative … we are happy to go from position alpha.”
The supervisor later told investigators that he did not hear this transmission. The trainee said that although he realized the aircraft was at Bravo, rather than Alpha, he “did not consider correcting [the crew], as he had been told not to be forceful toward pilots.” The trainee also said he believed a takeoff from Bravo was within the 777’s performance capability.
The copilot realized that “something was not right” when he saw grass beneath the nose just after the aircraft became airborne, the report said. “As the commander appeared not to be unsettled by the departure and there was a member of the cabin crew on the jump seat, he did not speak his concerns to the commander during the sector.”
The commander apparently did not realize the error until he was confronted by the station engineer after the 87 passengers and 14 crewmembers disembarked at Antigua. He filed an air safety report and notified the airline’s flight crew manager of the incident.
Wind Shift Leads to Overrun
Boeing 737-800. Substantial damage. No injuries.
As the 737 neared Limoges–Bellegarde (France) Airport the afternoon of March 21, 2008, the automatic terminal information service (ATIS) indicated that Runway 21 was in use, with winds from 280 degrees at 13 kt with gusts to 25 kt. However, the ATIS information was nearly an hour old, and a strong cold front was approaching the airport. “The passage of a cold front causes rapid variations in wind direction and intensity, generally accompanied by heavy precipitation,” said the report by the French Bureau d’Enquêtes et d’Analyses.
The flight crew selected a reference landing speed of 143 kt and added 15 kt for an approach speed of 158 kt. They decided to use 30 degrees of flap for the approach, rather than 40 degrees, to improve handling in the anticipated crosswind and gusts. The autobrake was set to position 3, which is above the minimum but below the maximum setting recommended for a wet runway.
The airplane’s weather radar system depicted an area of moderate precipitation near the airport, and the crew requested and received approval by air traffic control (ATC) to climb to 4,000 ft while tracking the runway centerline if they had to conduct a missed approach.
The crew encountered a 50-kt right crosswind and increasing precipitation as they began the instrument landing system (ILS) approach. The 737 was 4 nm (7 km) from the runway when the airport traffic controller cleared the crew to land and advised that the surface winds were from 330 degrees at 20 kt with gusts to 35 kt and that the runway was wet. “The crew acknowledged without reading back and continued the approach,” the report said. It noted that despite the information provided by the controller, the crew was “not fully aware” that the wind had shifted and intensified.
The copilot, the pilot flying, disengaged the autopilot and autothrottle at a height of 300 ft. The airplane entered a very heavy rain shower on final approach and deviated slightly above the glideslope. “During the flare, while the rain was intensifying on the runway, the captain took control of the airplane,” the report said.
The available landing distance on Runway 21 is 2,440 m (8,005 ft). The 737 touched down to the left of the runway centerline about 690 m (2,264 ft) beyond the approach threshold at an airspeed of 147 kt and a groundspeed of 155 kt. The spoilers deployed automatically. The captain promptly applied reverse thrust but then returned the thrust levers to idle and disengaged the autobrake because he was experiencing difficulty in maneuvering the airplane toward the centerline. The engines were at idle for about 10 seconds and took almost eight seconds to “power up” after the captain reapplied reverse thrust, the report said.
The airplane overran the runway at 45 kt and came to a stop about 50 m (164 ft) beyond the threshold. “The captain called for an emergency evacuation,” the report said. “The engines were damaged by the ingestion of earth and stones, and the airplane was bogged down. Extensive excavation work was required in order to be able to tow the airplane back to the runway.” There were no injuries among the 175 passengers and six crewmembers.
During postaccident interviews, “the crew stated that they did not pay attention to the wind information provided by the controller when the airplane was on final,” the report said. “They kept in mind a crosswind coming from the right with a headwind [component], in accordance with the ATIS. They added that they would have aborted the approach if they had been aware of the tail wind.”
In-Flight Vibration Traced to Aileron
Airbus A320-232. No damage. No injuries.
Shortly after the A320 departed from Mackay, Queensland, Australia, the afternoon of May 18, 2009, the electronic centralized aircraft monitor (ECAM) displayed an “aileron servo fault” message. “A review of the flight deck documentation did not identify any specific procedures for the crew to action and [indicated] that the caution was for crew awareness only,” said the report by the Australian Transport Safety Bureau (ATSB). “As there were no other caution messages and the flight controls were operating normally, the flight crew decided to climb to the cruise altitude of Flight Level (FL) 350 and continue to Melbourne.”
After leveling at FL 350, the crew detected a vibration that they later described as “a light continuous shaking.” The ECAM indicated a left aileron oscillation of five degrees and a fault in the autopilot’s no. 1 elevator/aileron computer (ELAC). The fault caused the no. 2 ELAC to take over primary control of the ailerons.
The pilot-in-command (PIC) asked the cabin manager to visually check the left wing. The cabin manager reported that the left wing was moving up and down, and that there was “quite a bit of shaking” in the aft cabin. The copilot looked out the left window and confirmed that the left aileron was oscillating and that the left wing was moving up and down about 1 m (3 ft).
The PIC varied airspeed but noticed no change in the vibration or in the aileron oscillation indicated on the ECAM.
The pilots decided to divert the flight to Gold Coast Aerodrome in Coolangatta, Queensland. The vibration, aileron oscillation and wing flexing intensified as the A320 descended through FL 200. After consulting the quick reference handbook, the crew deactivated the no. 1 ELAC. Noticing no change, they reactivated the no. 1 ELAC. The vibration and aileron oscillation ceased. “The crew reported no further control problems or ECAM messages during the remainder of the descent, approach and landing,” the report said.
Examination of the aircraft revealed that the aileron oscillation had been caused by two separate faults in the autopilot system. The first was an intermittent internal fault in the no. 1 ELAC. The resulting automatic transfer of primary control of the ailerons to the no. 2 ELAC led to activation of a faulty servo that caused the aileron to oscillate. When the PIC reactivated — and thus reset — the no. 1 ELAC, the faulty servo was isolated.
“The [servo] fault was introduced during manufacture by an incorrect adjustment of the servo, which caused internal wear in a number of the servo’s hydraulic control components,” the report said. “The aileron servo manufacturer has incorporated a new method of adjusting the aileron servos during assembly to minimize the likelihood of a recurrence of the problem.”
Investigators found that a nearly identical incident had occurred in the same aircraft eight months earlier but had not been reported to ATSB. “The operator has improved the training of its staff and the reportable event requirements in its safety management system manual in an effort to address the non-reporting risk,” the report said.
Wheel Explodes During Tire Inflation
Bombardier CRJ200. Substantial damage. One serious injury.
While preparing for a flight from Manchester, England, the morning of Nov. 13, 2008, a flight crewmember noticed a small cut in a main landing gear tire and reported it to the airline’s main engineering control center in Germany. The damage was determined to be beyond acceptable limits, and the flight was canceled.
The airline sent a maintenance technician and spare parts to Manchester the next morning. In addition to replacing the damaged tire, the technician was assigned to conduct a five-day maintenance check of the CRJ, which included a check of tire pressures. He decided to check the pressures in the undamaged tires before replacing the damaged tire and found that the right nosewheel tire was slightly underinflated.
The AAIB report said that the technician was not familiar with the nitrogen pressure rig that had been provided, and he had difficulty operating it. When he pressed the inflator lever, he perceived that nitrogen was not entering the tire. “He pressed the inflator lever once or twice again, and the wheel burst,” the report said. “Wheel fragments were scattered across the apron, and serious injuries were inflicted on the technician.”
The report noted that the nosewheels on the CRJ had not been equipped with optional overpressure relief valves. Normal inflation pressure was 163 psi (11 bar), and overinflation tests by the manufacturer had shown that the wheel would fail at about 997 psi (69 bar).
Investigators were unable to identify the manufacturer of the nitrogen pressure rig. It apparently was one-of-a-kind and displayed no operating instructions or warning labels. The rig was capable of supplying pressures far beyond those required for aircraft tires. The regulator was set for 1,000 psi (69 bar), and the delivery-pressure gauge was marked in bar, rather than in psi, with a full-scale reading of 400. The report said that a technician unfamiliar with the rig might not realize that only slight depression of the inflator lever and a small deflection of the gauge needle were required to inflate an aircraft tire.
The report noted that the CRJ200 was certified before the European Aviation Safety Agency and the U.S. Federal Aviation Administration required overpressure burst protection for the tires of newly certified transport category airplanes. The AAIB recommended that the requirement be extended to all transport airplanes.
“If overpressure burst protection had been fitted to this aircraft, it is probable that the accident would not have occurred,” the report said. “This is not the first occasion on which such bursts have happened, and previous such events have resulted in fatalities.”
Too Heavy to Fly
Cessna 208B. Destroyed. Three fatalities, one serious injury.
Witnesses to the Caravan’s departure said that the airplane traveled far down the 1,976-m (6,483-ft) runway with its nosewheel in the air before it lifted off and cleared the airport boundary fence by about 10 ft. The aircraft climbed about 300 ft, sank about 100 ft when the pilot apparently retracted the flaps, turned right, pitched into a nose-high attitude, stalled and spun to the ground. One passenger survived with a spinal injury. There was no fire.
The accident occurred at Eros Airport in Windhoek, Nigeria, the morning of Nov. 15, 2009. Airport elevation is 5,686 ft, the outside air temperature was 19 degrees C (66 degrees F), and surface winds were from 180 degrees at 8 kt. The Nigerian Directorate of Aircraft Accident Investigations found that the Caravan was 629 lb (285 kg) over its maximum takeoff weight when it departed from Runway 19, which has an unspecified upslope with rising terrain and mountains in the departure area.
The aircraft was operated by a South African company and was scheduled to fly to several airports in Angola. “On board the aircraft was a substantial amount of cargo, which consisted mainly of building material, several containers of paint, boat spares, tool boxes, liquid beverages and frozen meat,” the report said. The handling agent at Eros Airport had weighed a “certain amount of the cargo,” but additional cargo that arrived just before departure was not weighed before it was loaded into the cargo pod.
“The suitcases of the three passengers and the pilot were also not weighed and were loaded inside the cabin toward the back,” the report said. “The cargo inside the cabin was not secured and was placed between and on top of the seats all the way to the roof.”
The aircraft had been modified according to a supplemental type certificate that extended its maximum takeoff weight from 8,750 lb (3,969 kg) to 9,062 lb (4,110 kg). The load sheet for the flight indicated that the aircraft was within weight and balance limits. However, reconstruction of the loading by investigators showed that the actual takeoff weight was 9,691 lb (4,396 kg). The greatest error found in the pilot’s calculations was his use of 4,575 lb (2,075 kg) for the aircraft’s empty weight. “The pilot obtained the aircraft empty weight from the sample loading problem in the pilot’s operating handbook (POH),” the report said. The actual empty weight was 599 lb (272 kg) higher, at 5,174 lb (2,347 kg). The report provided no analysis of the aircraft’s center of gravity or whether the unsecured load had shifted in flight.
Among the investigation’s key findings was that the wing leading edges had been “spray-painted with a harsh anti-erosion type paint,” the report said. “This type of paint results in a rough texture which can therefore affect the stalling characteristics of the wing. Verification with the aircraft manufacturer confirmed that this did not meet the original airworthiness certification requirements and was in contradiction of the manufacturer’s minimum continuous airworthiness standard.”
Rivet Causes AC Failure
Bombardier Q400. Minor damage. No injuries.
After departing from London Gatwick Airport with 72 passengers and four crewmembers for a flight to Düsseldorf, Germany, the morning of Dec. 21, 2009, the aircraft was climbing through 6,000 ft when the alternating current (AC) electrical system failed. The flight crew declared an urgency and requested and received clearance to return to Gatwick.
“The commander, as pilot monitoring, handed responsibility for radio communications to the copilot and began conducting procedures listed in the emergency checklist,” said the AAIB report.
After the aircraft descended out of icing conditions, “the airframe appeared clear of ice, [but] the pilots elected, as a precaution, to conduct the approach using flap 35 at increased speed in accordance with company procedures for flight in icing conditions,” the report said. “The landing was uneventful.”
Examination of the aircraft revealed significant fire damage to the wiring loom routed within the trailing edge of the left wing center section. “The damage was localized to an area where the loom was supported by plastic tie straps attached to a support bracket riveted to the lower wing skin,” the report said. One of the tie straps, the fiberglass tape wrapped around the loom and some of the 22 wires in the loom had chafed against the head of one of the blind rivets, causing electrical arcing and a fire.
“The aircraft manufacturer has since issued a modification to replace the blind rivets with solid rivets and to inspect the wiring for damage,” the report said.
Icing Induces Stall in Holding Pattern
Saab 340B. Substantial damage. No injuries.
The Saab was en route in visual meteorological conditions at 12,000 ft during a scheduled flight from Moranbah to Brisbane in Queensland, Australia, on Nov. 5, 2008, when ATC told the flight crew to enter a holding pattern with two-minute legs over a nondirectional beacon (NDB) in Gayndah.
The crew reduced airspeed to 160 kt and selected engine heat before the aircraft entered clouds with an outside air temperature of minus 5 degrees C (23 degrees F) as it neared the NDB. They activated the propeller deicing systems after entering the clouds. “The pilots noticed a buildup of soft ice on the windscreen wipers and a dusting of ice on the leading edges of the wings,” the ATSB report said. “They discussed activating the deice boots but decided not to.”
Airspeed decreased to 133 kt, and the PIC increased power until the engines reached the maximum interstage turbine temperature (ITT). As the aircraft turned over the NDB to begin the second circuit of the holding pattern, the pilots felt a buffet. There was no aural stall warning, and the stick shaker did not activate; however, the PIC perceived the buffet as a sign of an impending stall.
“The PIC disconnected the autopilot, applied substantial power (80 to 83 percent torque), initiated a descent and maintained the left turn to remain in the holding pattern,” the report said. The Saab exited the icing conditions at 10,000 ft and was landed without further incident in Brisbane. Both engines had to be replaced because their ITT limits had been exceeded during the stall recovery.
The report did not discuss the crew’s decision not to activate the deice boots but noted that Saab later revised its standard operating procedures to eliminate pilot discretion and require that deice boots be activated in continuous mode when entering icing conditions.
Control Lost on Night Takeoff
Cessna 402. Destroyed. One fatality.
Visibility was 5 mi (8 km) in light rain and mist, and the ceiling was overcast at 400 ft when the pilot departed from Runway 33 at Martha’s Vineyard (Massachusetts, U.S.) Airport for a positioning flight to Boston the night of Sept. 26, 2008. ATC had cleared the pilot to climb to 4,000 ft and turn right to a heading of 360 degrees, said the report by the U.S. National Transportation Safety Board (NTSB).
Recorded ATC radar data showed that the 402 climbed to 700 ft, made a slight left turn and then a right turn that continued until radar contact was lost. The airplane struck trees and crashed between two houses about 3 nm (6 km) northwest of the airport.
“Analysis of the radar and weather data indicated that, with the flight accelerating and turning just after having entered clouds, the pilot likely experienced spatial disorientation,” the report said. The pilot, 61, held an airline transport pilot certificate and had 16,746 flight hours, including 2,330 hours in 402s.
‘Encountered a Sinker’
Piper Chieftain. Substantial damage. No injuries.
A local weather station was reporting winds from 110 degrees at 24 kt with gusts to 35 kt as the pilot neared the destination, Nondalton, Alaska, U.S., during a positioning flight on Oct. 10, 2009. The pilot told investigators that the Chieftain “encountered a sinker” — a strong downdraft — on final approach and began to descend below the intended glide path.
“He added full engine power to stop the descent, but the airplane continued to descend, and it landed hard on the right side of the runway,” the NTSB report said. “The landing gear collapsed, and [the airplane] slid about 150 yards [137 m], resulting in substantial damage to the fuselage.”
Collision With an Automobile
Cessna 421B. Substantial damage. No injuries.
After landing at Hearst Castle Airstrip in San Simeon, California, U.S., the afternoon of Oct. 2, 2009, the pilot taxied the 421 to the parking area, which appeared to be level. He did not set the parking brake, as required by the checklist, before shutting down the engines, securing the airplane and leaving the cockpit to open the cabin door for the five charter passengers.
The airplane rolled backward and struck a parked automobile. The 421’s empennage was substantially damaged. “Although the parking area appeared level, the pilot indicated that later analysis showed there was a gradual slope,” the report said.
External Load Snags Trees
Bell 206B. Substantial damage. One serious injury.
The helicopter was involved in an external-load operation, hauling tree limbs from a logging site in a steep ravine to a collection site at the top of the hill near Cougar, Washington, U.S., on Oct. 10, 2008. Witnesses saw the load at the end of the 60-ft (18-m) long line become entangled in trees as the helicopter departed from the logging site, the NTSB report said.
The pilot told investigators that the helicopter suddenly rolled right and that he had difficulty moving the cyclic control. “He continued to try to fly uphill to a dirt road but had little control over the helicopter,” the report said. The low-rotor-speed warning horn sounded, and the pilot released the load as the helicopter yawed right, pitched nose-down and descended to the ground.
Tail Rotor Control Cable Snaps
Aerospatiale Alouette III. Substantial damage. No injuries.
The ex-military helicopter was en route to a fire-fighting base in Hogsback, South Africa, the morning of June 3, 2009. The pilot chose an open field on which to land, but on final approach, the helicopter suddenly yawed left. It was about 3 ft above the ground when the pilot lost control of the tail rotor.
“The pilot reacted quickly to correct the situation by slowly lowering the collective pitch control lever so that the helicopter could descend onto the ground,” said the report by the South African Civil Aviation Authority. “The pilot’s intention was to avoid a hard landing.”
When the helicopter touched down, however, the torque of the main rotor caused it to yaw and roll over onto its right side, the report said. Damage was substantial, but the pilot and the crewmember aboard the helicopter were not injured.
Examination of the wreckage revealed that the tail rotor control cable had broken where it is routed around a pulley beneath the floor. The report said that the cable had been contaminated by dust and oil, which caused friction between the cable and the pulley, and the eventual failure of the cable.
R44 Hits House in Night IMC
Robinson R44 II. Destroyed. Two fatalities.
Night instrument meteorological conditions prevailed when the non-instrument-rated private pilot departed from a casino near Whiting, Indiana, U.S., for a flight to Kenosha, Wisconsin, on Sept. 21, 2008. About 30 minutes later, a policeman heard the helicopter pass overhead at about 500 ft. “He did not see the helicopter or its lights due to dense fog,” said the NTSB report. “He stated that the visibility there was about 300 to 500 ft.”
Shortly thereafter, the R44 crashed into a house about 1.5 nm (2.8 km) from the Kenosha airport, which was reporting 3/4 mi (1,200 m) visibility in mist and a 100-ft overcast. The pilot and passenger were killed, but none of the five occupants of the house was hurt.
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