The following information provides an awareness of problems that might be avoided in the future. The information is based on final reports by official investigative authorities on aircraft accidents and incidents.
Heavy Rain on Takeoff
Bombardier CRJ700. No damage. No injuries.
The CRJ was cruising at 35,000 ft during a scheduled flight with 66 passengers and four crewmembers from Oklahoma City, Oklahoma, U.S., to Chicago the morning of April 18, 2010, when the flight crew noticed that the airplane was not turning normally toward a navigation waypoint. The pilots also received a warning that the automatic flight control system was encountering excessive aileron forces.
“The captain disconnected the autopilot and attempted manual control of the ailerons,” said the report by the U.S. National Transportation Safety Board (NTSB). “He found that aileron forces were excessive and response to aileron control was limited.”
While responding to the control problem, the crew pulled the roll-disconnect handle, which segregates roll control, with the left control wheel controlling only the left aileron and the right control wheel controlling the right aileron.
None of the corrective actions reduced the excessive control forces or improved aileron response. The crew decided to divert the flight to Kansas City, Missouri. The CRJ was descending through about 20,000 ft when aileron control returned to normal. The airplane subsequently was landed at Kansas City without further incident.
Recorded flight data showed that the ailerons had responded normally during preflight control checks and during the departure in heavy rain. The airplane encountered ambient temperatures below freezing in instrument meteorological conditions (IMC) about 11 minutes after takeoff.
“During climb, about 20 minutes into the flight, FDR [flight data recorder] data indicates that the left aileron … was not responding properly to autopilot inputs,” the report said. “The right aileron was responsive to autopilot inputs.”
After the autopilot was disengaged, manual control forces up to 25 lb (11 kg) resulted in only slight movement of the interconnected ailerons. The report said that the left and right aileron control circuits remained bound after the roll-disconnect handle was pulled.
The control binding ceased when the captain applied a control wheel force of 34 lb (15 kg) for 6 seconds as the airplane descended into warmer air.
“Examination of the control system did not reveal any areas where [mechanical] binding had occurred,” the report said. “However, the events of the flight were consistent with water accumulating in the aileron control system, freezing at higher altitudes and temporarily binding the aileron control system.”
Two Excursions in Two Days
Boeing 737-900ERs. Minor damage. No injuries.
The combination of rubber deposits and standing water on the runway significantly reduced braking effectiveness and likely led to the landing excursions of two 737-900ERs on consecutive days at the airport in Pekanbaru, Indonesia, according to reports published recently by the country’s National Transportation Safety Committee (NTSC).
Significant tailwinds also were among factors similar to both serious incidents, which occurred on February 14 and 15, 2011, on Runway 36 at Pekanbaru and involved aircraft operated by the same company.
In the first incident, the 737 was en route from Jakarta with 212 passengers and seven crewmembers. Nearing Pekanbaru, the flight crew was advised that visibility was 1 km (about 5/8 mi) in heavy rain. They entered a holding pattern until visibility increased to 3 km (2 mi), which was above the minimum required to conduct the instrument landing system (ILS) approach to Runway 36.
Although the tower controller advised the crew that surface winds were calm, they noticed that the flight management system (FMS) was showing a tailwind of 11-12 kt.
The landing proceeded without incident until the thrust reversers were stowed at 70 kt about 1,000 ft (305 m) from the end of the 7,349-ft (2,240-m) runway. “According to performance calculations, the aircraft should [have been] able to stop on the remaining runway,” the report said. However, even after applying maximum manual braking, the pilot felt no significant deceleration.
The aircraft came to a stop with the right main landing gear off the side of the runway. Examination of the runway revealed areas of standing water up to 3 cm (1 in) and buildups of rubber near the departure end.
“The failure of the aircraft to stop most likely [was] due to the significant deterioration of both the runway friction and brake effectiveness as [the] result of the existing combination of rubber deposits and water spots,” the report said.
The next evening, the crew of another 737-900, inbound from Medan with 226 people aboard, conducted the ILS approach and landing on Runway 36 in light rain. Although the tower controller advised that the surface winds were calm, recorded flight data showed a 15-kt tailwind. In this case, however, “the pilot did not see the wind information in the computer display unit,” the report said.
Hearing the crew of a preceding aircraft report that the runway was slippery, the 737 pilot set the autobrakes to maximum. However, investigators determined that under the existing conditions, “the runway length available was not sufficient for the aircraft to stop on the runway.”
Similar to the incident the day before, the landing proceeded normally until the thrust reversers were stowed. Deceleration decreased, and the pilot applied maximum manual braking and redeployed the thrust reversers. The aircraft came to a stop 12 m (39 ft) off the end of the runway.
There were no injuries in either incident, and aircraft damage was minor.
The report noted that the airport operator scheduled runway cleanings every six months, and the last one had been performed about six weeks before the incidents occurred. However, post-incident tests showed that runway skid resistance was below the minimum requirement, resulting in poor braking action when the runway was wet.
The incorrect wind velocity reports provided by the tower controllers were attributed to inaccuracies resulting from turbulence created by nearby buildings and vegetation surrounding the airport’s anemometer.
Following the incidents, the airport authority repaired the runway surface to prevent accumulations of standing water and established a new requirement for “on-condition” runway cleaning.
Thrown Forward on Touchdown
Boeing 767-300. Substantial damage. No injuries.
Before departing from Cancún, Mexico, on Oct. 3, 2010, the flight crew examined a forecast indicating that visual meteorological conditions (VMC) would prevail at the estimated time of arrival at the destination, Bristol, England.
As the aircraft neared Bristol, however, the airport was reporting 1,400 m (7/8 mi) visibility in rain and mist, scattered clouds at 100 ft and a broken ceiling at 400 ft, said the report by the U.K. Air Accidents Investigation Branch (AAIB).
While conducting the ILS approach to Runway 09, the commander saw an FMS indication of a 52-kt crosswind. The tower controller advised that the surface winds were from 120 degrees at 12 kt, visibility was 3,000 m (about 2 mi) in moderate rain and that the runway was wet.
The commander recalled that there was “a surprising amount of turbulence” during the approach. He asked the copilot to monitor the FMS wind display and call out any substantial change.
The 767 was about 400 ft above the ground when the commander spotted the runway. The report noted, however, that his vision was somewhat obscured by rain on the windshield, despite use of the windshield wipers. Because of undulating terrain, the ILS glideslope cannot be used below 200 ft, and only the initial portion of the runway can be seen on approach.
The commander disengaged the autopilot and autothrottle, and hand flew the final approach. Both pilots confirmed that the precision approach path indicator (PAPI) showed that the aircraft was on the proper glide path. The report noted, however, that the proper tracking of the PAPI glide path resulted in several nuisance “GLIDESLOPE” warnings by the enhanced ground-proximity warning system.
“The commander recalled making a normal nose-up pitch input prior to touchdown and that the touchdown was unusually hard,” the report said. FDR data indicated a peak vertical acceleration of 2.05 g when the aircraft touched down on the main landing gear.
“Both the commander and copilot reported that they were thrown forward during the touchdown, and that this resulted in the commander inadvertently moving the control column forward, to a nose-down position,” the report said, noting that the pilots had not locked the inertia reels on their shoulder straps. “The aircraft then rapidly de-rotated before the nose gear contacted the runway.”
None of the 270 people aboard the aircraft was injured during the hard landing, and the aircraft was taxied to the stand. The commander filed a hard landing report, and subsequent inspection of the 767 revealed substantial damage to forward fuselage crown skins and stringers.
Investigators found that the operator’s flight monitoring system had not revealed an unusually high rate of hard landings (i.e., those involving peak vertical accelerations of 1.8 g or more) on Bristol’s Runway 09. “This accident might have been avoided if the unusually high rate of hard landings by Boeing 767 aircraft on Runway 09 had triggered safety action to reduce the rate or stop operations of the type onto the runway,” the report said.
Turbulence Hurts Cabin Crew
Airbus A340-300E. No damage. Two serious injuries.
Inbound from Dakar, Senegal, the A340 was about 100 nm (182 km) from the destination in Johannesburg, South Africa, the afternoon of Dec. 29, 2012, when the flight crew switched on the “Fasten Seat Belt” signs.
“The flight deck crew indicated that although it was cloudy during the descent with isolated thunderstorms visible, the weather radar did not indicate turbulence or moisture in the clouds that deemed it necessary to instruct the cabin crew to take up their seats and fasten their harnesses,” said the report by the South African Accident and Incident Investigation Division.
The A340 was descending through 20,676 ft about 10 minutes later when it encountered severe turbulence. Recorded flight data indicated that the turbulence lasted about 8 seconds and caused peak vertical accelerations ranging from +1.551 g to –0.121 g.
“Two cabin crewmembers, who were busy in the rear galley of the aircraft securing trolleys and bins, suffered serious injuries due to falls and collisions with aircraft furnishings, as they were not seated nor restrained at the time,” the report said. None of the other 241 people aboard the aircraft was hurt.
“One of the cabin crewmembers could not get up from the floor,” the report said. “The other member managed to use the interphone and informed the in-flight service coordinator of their injuries,” the report said.
The captain reported the injuries to air traffic control (ATC) and requested and received clearance for a priority approach and landing at Johannesburg. “The aircraft was met by paramedics at the parking bay, and the two injured cabin crewmembers were stabilized, removed from the aircraft via a passenger assistance unit and transported to hospital via ambulance,” the report said.
Faulty APU Emits Smoke
Boeing 757-200. No damage. One minor injury.
The passengers were disembarking from the 757 after a flight from Dalaman, Turkey, to Glasgow, Scotland, the afternoon of Oct. 11, 2012, when the commander detected a strong odor and saw a blue haze emanating from behind the instrument panel and the overhead circuit breaker panel.
The engines had been shut down, but the auxiliary power unit (APU) was operating. The commander initially suspected an electrical fire, but the odor and the density of the haze suggested otherwise, the AAIB report said. He opened the flight deck door and saw that the passenger cabin was filling with thick smoke.
The passengers in the forward cabin already had exited, and the commander ordered an immediate evacuation of all the remaining passengers. The flight attendants and the copilot assisted them in using escape slides as well as the airbridges to get out of the aircraft. One of the 231 passengers sustained minor injuries during the evacuation.
“The APU was identified as the source of the smoke and fumes in the cabin,” the report said. It was declared inoperative and scheduled for return to the manufacturer three days later for a detailed examination.
The 757 departed from Glasgow the next morning for a flight with 241 passengers and eight crewmembers to Tenerife, Spain. The flight crew, who were aware of the previous incident, detected a strong odor of fuel or oil during takeoff. “As the aircraft reached its cruise altitude, both pilots started to feel unwell, with some lightheadedness and dizziness,” the report said.
The pilots donned their oxygen masks, declared an urgency and diverted the flight to Manchester, England. The cabin was not affected by smoke or fumes, and the flight crew’s symptoms subsided during the diversion. They landed the 757 without further incident in Manchester.
“The aircraft underwent an engineering check, and engine ground runs were carried out,” the report said. “No further faults were found, and it was suspected that some residual oil may have remained in the conditioning or equipment cooling systems after the previous day’s incident and associated engineering activity.”
Pilots Agree to Press On
CASA 212-200. Destroyed. Eighteen fatalities.
The aircraft departed from Medan, Indonesia, for an unscheduled 30-minute visual flight rules (VFR) flight to Kuta Cane the morning of Sept. 29, 2011. Although VMC prevailed over most of the route, the cockpit voice recorder (CVR) captured a conversation between the pilots about clouds ahead and the absence of a gap to fly through.
“Both pilots agreed to fly into the cloud,” said the NTSC report.
The CVR recording indicated that the pilots became uncertain about the aircraft’s position shortly thereafter. The report said that this likely resulted from loss of situational awareness when the crew lost visual reference with the ground. About 25 seconds after the pilots agreed to continue the VFR flight into IMC, the CVR recording ceased.
Searchers tracked the CASA’s emergency locator transmitter signal to where the aircraft had struck a steep mountain slope at 5,055 ft about 16 nm (30 km) from the Kuta Cane airport. All 18 people aboard the aircraft had been killed.
The report said that inadequate crew coordination due to a “steep cockpit transition gradient” was a factor in the accident. There was no evidence that the pilots used checklists or conducted any briefings. Moreover, “the investigation did not find any evidence that the flight crew had received ALAR [approach and landing accident reduction] and CFIT [controlled flight into terrain] training,” the report said.
Rudder Trim Disconnected
ATR 72-212A. No damage. No injuries.
Shortly after departing from Papeete, French Polynesia, for a scheduled flight the afternoon of June 25, 2011, the captain noticed that the ball in the slip indicator was displaced fully right.
“He used the rudder trim as far as the stop to reduce the load on the rudder,” said the report by the French Bureau d’Enquêtes et d’Analyses. “He managed to move the ball halfway back between the centre and the instrument right-hand stop.” The copilot confirmed that the ball in his slip indicator was in the same position.
Concerned that they would not be able to trim the airplane properly if the left engine failed, the flight crew turned back to Papeete. “During speed reduction on final, the crew indicated that the sideslip decreased,” the report said. “The crew landed without further mishap.”
Examination of the ATR revealed that the rudder trim tab control rod was not connected. Investigators found that a maintenance check had been completed the day before the incident occurred and that the control rod had been disconnected during repair of corrosion on the lower rudder torque tube.
After the torque tube was reinstalled, “the technician who closed up the access panels did not notice that the tab control rod was disconnected,” the report said. The anomaly was not found during subsequent post-maintenance visual inspections and a flight control deflection check.
The report said that factors contributing to the incident were initial work cards that did not detail disconnection of the trim tab control rod and limitations in the company’s maintenance computer system that prevented entry of intermediate stages in a maintenance task.
Flight Nurse Aids Sick Pilot
Beech King Air B200. No damage. No injuries.
The King Air was descending from 17,000 ft to 8,000 ft during a medevac flight from Bundaberg, Queensland, Australia, to Brisbane the afternoon of Nov. 5, 2012, when the pilot stopped responding to ATC communications. At ATC’s request, flight crews of other aircraft in the area tried to hail the pilot but were unsuccessful.
Before beginning the descent, the pilot had engaged the autopilot’s vertical navigation mode and had set 8,000 ft in the altitude selector. The autopilot subsequently leveled the aircraft at an altitude recorded by ATC as 8,100 ft. The power levers remained in the position set for the descent, however, and airspeed began to decrease.
“As the flight continued, the flight nurse became concerned, as she had not yet sighted the geographic features she normally observed,” said the report by the Australian Transport Safety Bureau. “The nurse then turned her VHF radio on and heard a number of broadcasts from various persons attempting to contact [the pilot].”
The flight nurse checked on the pilot and found that his chin was slumped onto his chest and that he was not alert. She was attempting to rouse the pilot when the aircraft pitched nose-up, and the stall warning horn sounded.
“The pilot regained alertness and initiated recovery actions,” the report said. “He reported disconnecting the autopilot and applying an amount of engine power.”
The flight nurse monitored the pilot’s condition as he re-established radio communications with ATC and followed vectors for an approach to Brisbane. Shortly after he switched to the tower frequency, he began to hyperventilate, and his hands began to shake; but he was able to land the aircraft.
“The nurse recalled that the landing and subsequent taxi speed appeared faster than normal [and that] the pilot’s emotional and physical state worsened,” the report said. “She encouraged the pilot to complete the ‘After Landing’ checklist and offered reassurance.”
The pilot’s physical condition improved slightly as he parked the aircraft and shut down the engines. The flight nurse summoned assistance in helping deplane the two patients and the pilot. “The emotional and physical state of the pilot at the time was reported as poor,” the report said.
The report did not specifically state the cause of the pilot’s incapacitation but noted that drug testing “returned a positive reading for an illicit substance which had affected the pilot’s sleep cycle.” Investigators found that he had begun reporting significant sleep disturbances four days before the incident and that “the pilot was experiencing a fatigue level well above that of a normal day worker when ready to retire to bed.”
The report noted that the flight nurse had completed annual cabin safety and emergency training provided about six months before the incident occurred: “The training provided guidance on how to respond to a pilot incapacitation from both a medical and operational perspective. This included using the autopilot, the communications system, the flaps, landing gear and power levers.”
The flight nurse said, however, that more practical training on using the aircraft’s radios would be beneficial. The operator subsequently revised its cabin safety and emergency training, and developed a “First Actions” checklist to guide flight nurses in responding to pilot incapacitation.
‘We’re Losing It’
Cessna 340A. Destroyed. Three fatalities.
About 14 minutes after departing in IMC from Chehalis, Washington, U.S., for a business flight the morning of Oct. 25, 2010, the pilot reported an engine failure and that he was returning to the airport.
Recorded ATC radar data showed that the airplane was at 14,800 ft when it began a right turn at a turn rate of 8 degrees per second. Shortly thereafter, the airplane began a rapid descent, and the pilot radioed, “We’re losing it.”
The descent rate averaged 5,783 fpm until radar contact was lost at 10,700 ft. “The airplane impacted a 30-degree slope of a densely forested mountain at about 2,940 ft in a near vertical, slightly right-wing-low attitude,” the NTSB report said. All three occupants were killed in the crash, which occurred near Morton, Washington.
The report said that, based on the findings of the investigation, “it is most likely that the pilot experienced a partial loss of power of the right engine and, after incorrectly initiating a right turn into the failed engine, allowed the rate of turn to increase to the point that the airplane became uncontrollable before impact with terrain.” The cause of the power loss was not determined.
Unaware of Closed Runway
Piper Seneca II. Substantial damage. No injuries.
Before departing from Carrizo Springs, Texas, U.S., the evening of April 3, 2012, the pilot contacted a flight service specialist and asked if there were any temporary flight restrictions along his intended route to San Marcos. The specialist advised that there were none.
The NTSB report said that the pilot did not request a standard briefing or specifically request information about pertinent notices to airmen (NOTAMs). Therefore, he was not aware of a NOTAM that had been issued a week earlier to advise that Runway 08/26, one of three runways at San Marcos, was closed for construction.
As the Seneca neared the destination at dusk, the pilot listened to the automatic terminal information system (ATIS) broadcast, which did not include information about the runway closure, the report said. The control tower was closed.
After landing on Runway 08, the airplane struck construction barriers. The main landing gear separated, and the left wing was substantially damaged. The pilot, alone in the airplane, was not hurt.
The report said that the probable cause of the accident was “the pilot’s failure to ensure that he was aware of the NOTAM describing the runway closure” and that a contributing factor was “the failure of air traffic control personnel to include the runway closure information on the recorded ATIS information.”
Haste Makes Waste
Cessna 310. Substantial damage. One serious injury, two minor injuries.
The pilot and two friends were having lunch at Avalon, California, U.S., on Oct. 3, 2010, when the pilot noticed that the weather conditions were deteriorating rapidly. The pilot, who did not hold an instrument rating, told his friends that they should depart on their planned flight to Santa Ana while VMC still prevailed.
After boarding his two passengers, the pilot, who had flown the 310 to Avalon from Santa Ana earlier that morning, started the engines and performed an abbreviated engine run-up while taxiing to the runway.
“The takeoff roll was normal, but about 2 to 3 seconds after liftoff, the left engine failed and the airplane veered to the left,” the NTSB report said. “The pilot pushed the nose down to maintain airspeed, and the airplane entered a cloud/fog bank, impacted terrain and was engulfed by fire.” One passenger was seriously injured; the other passenger and the pilot sustained minor injuries.
Examination of the 310 revealed that the fuel selector for the left engine was in a position between “OFF” and the normal takeoff setting. “The pilot stated that it was his habit to shut off both fuel selector valves after each flight and that he did so after the previous landing,” the report said.
The report concluded that the pilot likely did not notice the incorrect positioning of the fuel selector in his haste to depart from Avalon: “Residual fuel in the lines, gascolator and carburetor, combined with the limited flow capability of the misset selector valve, permitted the engine to be started and operated normally at low rpm. However, the high fuel flow demand of the engine operating at full power could not be maintained by the misset valve, and the engine failed in the initial climb due to fuel starvation.”
Tail Rotor Effectiveness Lost
Bell 206B. Substantial damage. Three fatalities.
The pilot landed the JetRanger at New York’s East 34th Street Heliport to pick up two friends for a sightseeing flight the afternoon of Oct. 4, 2011. “The pilot had initially anticipated taking two passengers on the flight, but the two passengers brought two additional adults with them,” the NTSB report said.
The pilot kept the engine running while the passengers boarded. “The pilot did not conduct a safety briefing or mention life vests available on board the helicopter, complete performance planning or perform weight-and-balance calculations before takeoff,” the report said. Investigators determined that the JetRanger was 28 to 261 lb (13 to 118 kg) over maximum gross weight on takeoff.
During a left turn on departure, the low rotor rpm warning sounded and the helicopter yawed slightly right. The pilot turned back toward the heliport, inadvertently placing the JetRanger in a tailwind. “After the pilot increased collective pitch [to land], the helicopter entered an uncommanded right yaw that accelerated into a spin around the main rotor mast that could not be corrected by application of full left pedal,” the report said.
The helicopter descended into the East River, rolled inverted and sank. One passenger drowned, and two passengers later succumbed to their injuries; the fourth passenger and the pilot escaped injury.
The report concluded that the JetRanger likely had lost tail rotor effectiveness, which typically results in an uncommanded right yaw and occurs during maneuvers at high power and low airspeed in a tailwind or left crosswind, and is aggravated by high gross weight.
Main Rotor Strikes Tail Boom
Eurocopter AS350-B2. Substantial damage. No injuries.
The pilot was starting the engine in preparation to transport two passengers from a drilling platform in the Gulf of Mexico the afternoon of Oct. 7, 2011, when he felt abnormal vibrations. After shutting down the engine, he found that the main rotor blades had struck the tail boom.
The helicopter had been in a 23-kt headwind, with possible turbulence from nearby structures. The NTSB report concluded that the pilot likely had not properly centered and locked the cyclic before start.
“A review of accidents involving the same make and model helicopters revealed that in all of the recorded tail boom strikes by main rotor blades during start, two conditions needed to be present: cyclic not centered and air turbulence pushing strongly on the main rotor blades,” the report said.