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.
Mired in Mud
Dassault Falcon 20E. Substantial damage. No injuries.
The flight crew was assigned to conduct an electronic-warfare training mission with Royal Air Force pilots over the North Sea the morning of Aug. 9, 2012. The weather at the departure point, Durham (England) Tees Valley Airport, was good, with light winds.
The crew’s preflight calculations included 141 kt as V1, which is defined by British aviation authorities as the maximum speed at which the crew must decide to either reject or continue a takeoff following an engine failure, according to the report by the U.K. Air Accidents Investigation Branch (AAIB). Other European and U.S. civil aviation authorities, among others, define V1 as the speed at which action must be taken to reject or continue a takeoff, with the decision already made.
The Falcon was specially equipped to support military training missions and was close to its approved gross weight of 30,000 lb (13,608 kg) when the crew initiated the takeoff near the approach threshold of the 2,291-m (7,516-ft), dry runway.
“Takeoff was continued with the standard calls being made between the two pilots,” the report said. “These included calls on passing 80 kt and 100 kt, with the commander expecting the next call to be on passing the calculated V1 of 141 kt.”
During this time, the commander saw a large bird take flight from the runway and then fly toward the aircraft over the runway centerline. “The commander believed the bird represented a significant threat to the aircraft,” the report said. He later recalled that he announced “bird, aborting” at the same time the copilot called out “V1.”
However, investigators determined from limited recorded flight data (the operator had received an exemption from the requirements to equip the aircraft with a flight data recorder and a cockpit voice recorder) that the rejected takeoff (RTO) was begun 9 kt above V1.
The commander reduced thrust to idle, applied full manual braking and deployed the airbrakes; the Falcon was not equipped with thrust reversers or a drag chute. As the aircraft neared the end of the runway, the commander told the copilot to assist him on the brakes. “The copilot did so, but with no discernible effect on the aircraft’s deceleration,” the report said.
Deceleration was reduced when the Falcon overran the runway at 75 kt and entered the 119-m (390-ft) stopway and 60-m (197-ft) strip, which were covered by scattered loose gravel. The aircraft then came to a stop quickly when the landing gear sank into soft ground on contact with the runway end safety area. The pilots and the electronic warfare officer were not hurt, but the Falcon’s engines had ingested mud and stones, and the landing gear and wheel brakes had minor damage.
“The remains of a single carrion crow, weighing approximately 1.0 lb [0.5 kg], were recovered from the runway at a point approximately 1,400 m (4,600 ft) from the start of the aircraft’s takeoff roll,” the report said. Investigators believe that the bird had collided with the Falcon’s landing gear.
The report said that performance calculations showed that if the RTO had been initiated at 141 kt, the aircraft likely could have been stopped with 97 m (318 ft) of runway remaining.
Controller Overlooked Conflict
Embraer 135, 145. No damage. No injuries.
A controller’s “lack of monitoring and lack of awareness” led to a near midair collision between two Embraer regional jets at Chicago (Illinois) O’Hare International Airport the morning of Aug. 8, 2011, said the U.S. National Transportation Safety Board (NTSB).
The incident occurred in visual meteorological conditions and involved an ERJ-135, with 39 people aboard, that was on a visual approach to Runway 09R and an ERJ-145, with 45 people aboard and operated by a different airline, that was departing from Runway 32L.
The approach threshold of Runway 09R is east of Runway 32L; thus, the ERJ-135 would pass over Runway 32L on its way to land on Runway 09R.
The controller handling the ERJ-145 told investigators that he was “distracted by coordination requirements affecting two other airplanes” and had “overlooked the arriving airplane [the ERJ-135] during his scan” when he cleared the crew of the ERJ-145 for takeoff.
Shortly after the ERJ-145 reached rotation speed, the captain, the pilot monitoring, saw the ERJ-135 and told the first officer to delay the rotation. At about the same time, the controller said, “Traffic alert, left to right … stay as low as you can.” The captain responded, “Yeah, we’re doing that.”
Meanwhile, the controller handling the ERJ-135 had told the crew to go around. The NTSB said that the airplane crossed Runway 32L about 125 ft (38 m) above and 350 ft (107 m) in front of the ERJ-145.
Damaged Seal Causes Fuel Leak
Boeing 757-200. Minor damage. No injuries.
The 757 had undergone a C-check and two post-maintenance test flights, and was scheduled for an “airtest” prior to its release to service the afternoon of Aug. 7, 2012. The flight crew and a maintenance engineer conducted the airtest over the North Sea.
“Approximately three hours of the airtest had elapsed when, during a routine fuel check, the crew noticed a lateral fuel discrepancy of approximately 600 kg [1,323 lb], with the right wing fuel tank quantity indicating less than the left wing fuel tank,” the AAIB report said. Shortly thereafter, the imbalance reached 800 kg [1,764 lb], causing the engine indicating and crew alerting system to generate a “fuel configuration” warning.
While helping the pilots perform the applicable quick reference handbook checks, the engineer saw fuel leaking from the right engine. The leak was confirmed by the first officer. The commander then declared an urgency and requested and received clearance from air traffic control (ATC) to divert the flight to Newcastle (Scotland) Airport, about 85 nm (161 km) southwest.
“The flight crew then completed the ‘Engine Fuel Leak’ checklist by shutting down the right engine, following which they carried out an uneventful single-engine diversion and landing at Newcastle Airport,” the report said.
Examination of the Rolls-Royce RB211-535E4 engine showed that fuel was leaking from a flange on a fuel tube that runs from the high-pressure fuel pump to the fuel-flow governor. The fuel tube had been replaced during the C-check in compliance with a service bulletin.
Investigators found that one of the two bolts attaching the fuel tube flange to the high-pressure pump had damaged threads and was loose, and that the internal O-ring seal was damaged, with a section missing.
“Examination of the damaged thread forms showed that the bolt had not been cross-threaded, rather that the start thread of the wire-thread insert had ‘picked up’ during insertion of the bolt, causing a progressive rounding-over of the bolt’s thread as the bolt was tightened,” the report said, noting that the O-ring had been displaced and damaged during this process.
The fuel tube had been replaced while the engine was mounted in a transport cradle during the C-check. “The lower parts of the engine, including the area where the fuel tubes were to be replaced, were close to the ground and partially obstructed by the cradle’s steel framework,” the report said. “These restrictions made access significantly more difficult than if the engine had been mounted on its pylon or in an engine overhaul fixture.”
Smoke Traced to House Fire
Bombardier CRJ700. No damage. One serious injury.
The airplane had been dispatched for a scheduled flight from Denver to Chicago the night of July 18, 2012, with only one of the two air-conditioning packs of the environmental control system operative, according to provisions of the minimum equipment list. Due to adverse weather at Chicago O’Hare International Airport, the flight crew diverted to Peoria (Illinois, U.S.) International Airport.
The crew detected smoke during the approach to Peoria and ordered an emergency evacuation after landing. The two overwing exits and the main cabin door were used for the evacuation. One passenger suffered a broken ankle during the evacuation; the other 56 people aboard the airplane escaped injury.
An examination of the CRJ revealed no obvious source of the smoke. Investigators found, however, that the pack had failed on approach, allowing ambient air to enter the cockpit and cabin. The smoke likely was from a large house fire that the airplane had flown over on approach, the report said.
Improper Response to RA
Saab 340B, Beech King Air B200. No damage. No injuries.
The King Air was at 14,000 ft and inbound on an emergency medical services (EMS) flight to Broken Hill, New South Wales, Australia, the morning of Aug. 26, 2011, when the flight crew was advised by ATC that a Saab 340B had departed from the Broken Hill airport and was climbing on an opposite-direction heading to 17,000 ft.
The King Air was about 50 nm (93 km) east of the airport, in uncontrolled airspace, when the crew contacted the flight crew of the Saab on the common traffic advisory frequency (CTAF) and requested their current altitude. The Saab crew replied that they were climbing through 12,000 ft and were 27 nm (50 km) east of the airport.
“They further advised that [the King Air] was observed on their aircraft’s traffic-alert and collision avoidance system (TCAS) about 20 nm [37 km], in their 1 o’clock position,” said the report by the Australian Transport Safety Bureau. “The pilot of [the King Air] acknowledged the information and advised that he also had [the Saab] on his TCAS and that both aircraft were ‘well clear at the moment.’”
The Saab crew then changed their no. 2 radio from the CTAF frequency to the guard (emergency) frequency, leaving the no. 1 radio on the ATC frequency. “The pilot of [the King Air], however, expected the crew of [the Saab] to remain on the CTAF and maintain [13,000 ft], delaying their climb until after passing [the King Air],” the report said.
The King Air pilot attempted several times to tell the Saab crew that he would maintain 14,000 ft until passing the Saab, but there was no response on the CTAF frequency. He then received a TCAS traffic advisory and initiated a left climbing turn.
About the same time, the Saab was climbing through 13,200 ft when its TCAS issued a resolution advisory (RA) to “adjust vertical speed, adjust,” which requires reduction of vertical speed to the indicated value of 2,000, 1,000, 500 or 0 fpm. The first officer, the pilot flying, believing erroneously that they were above the King Air, disengaged the autopilot and initiated a climb while the captain advised ATC that they had received and were responding to a TCAS RA.
Lateral separation was 2.2 nm (4.1 km) when the aircraft passed each other at 14,200 ft. “About the same time, the captain of [the Saab] noted that the first officer’s actions were contrary to the RA and that he had initiated a climb instead of a descent,” the report said. “The captain immediately advised the first officer, who then commenced a quicker-than-expected descent. The captain then assumed control of the aircraft and reduced the descent. Separation between the aircraft began to increase, with [the Saab] descending through [14,000 ft] and [the King Air] climbing through [14,300 ft].”
There was no damage to either aircraft and no injuries to the 33 people aboard the Saab or the four people aboard the King Air. Both aircraft completed their flights without further incident.
“This incident emphasises the benefit of TCAS in assisting pilots with their awareness of other traffic,” the report said. “It is critical that pilots respond appropriately to a TCAS RA command.”
Inadvertent Fuel Shutoff
De Havilland Turbo Beaver. Substantial damage. No injuries.
The pilot was conducting an on-demand sightseeing flight near Cantwell, Alaska, U.S., the evening of July 7, 2012, when the engine abruptly lost power. “He attempted to restart the engine but was unable to, and elected to make a forced landing in a bog,” said the NTSB report.
The airplane’s left wing and right elevator struck trees during the landing, but the seven passengers and the pilot were not hurt.
“After the forced landing, the pilot noticed that the emergency fuel shutoff lever on the right side of the center console had been moved toward the shutoff position,” the report said. “The passenger who was seated in the right seat of the cockpit stated that he was unaware of the fuel shutoff lever and was not briefed on specific areas to be aware of in the cockpit. He had been adjusting himself in the seat just prior to the engine shutting down.”
Ditch Foils Off-Runway Landing
Cessna 208B Caravan. Substantial damage. No injuries.
The pilot said that he regularly landed the Caravan on the grassy area adjacent to the paved runway at the airport in Raeford, North Carolina, U.S., to minimize wear on the main landing gear tires. However, before Aug. 18, 2012, all the landings had been conducted in the same direction.
Returning from a skydiving flight that day, the pilot decided to land in the opposite direction. The airplane struck a ditch about 200 ft (61 m) from the touchdown point on the grassy area, became airborne again and landed hard, collapsing the nose landing gear and causing substantial damage to the fuselage. The pilot and his passenger escaped injury.
Control Lost After Power Loss
Cessna 310Q. Substantial damage. One fatality.
The airplane had just undergone an annual maintenance inspection, during which the fuel hose on the left engine had been removed and reinstalled to facilitate replacement of a cylinder. “A postmaintenance engine ground run was performed, and no discrepancies were noted,” the NTSB report said.
The owner picked up the airplane at Tupelo, Mississippi, U.S., the morning of Aug. 17, 2011. Witnesses heard sounds similar to a loss of power on takeoff and saw the 310 enter a descending left turn at about 500 ft. The landing gear separated when the airplane touched down on a road; the 310 then struck a vehicle and several trees before coming to a stop in front of a house. The owner/pilot was killed, but no one on the ground was hurt.
Investigators determined that the left engine had lost power on takeoff. “The B-nut connecting the fuel supply hose to the manifold valve on top of the left engine had backed off about a quarter turn,” the report said. During tests, the engine operated satisfactorily with the B-nut fully tightened but immediately lost power when the nut was loosened a quarter turn.
NTSB concluded that the probable cause of the accident was “the pilot’s delayed reaction in performing the engine failure procedures and his failure to maintain adequate airspeed, which resulted in loss of control” and that a contributing factor was “maintenance personnel’s improper torquing of the B-nut between the fuel supply hose and the manifold valve.”
Hard Impact Avoiding Geese
Piper Navajo. Substantial damage. No injuries.
The pilots were taking off from Washington County (Pennsylvania, U.S.) Airport with two passengers for an air taxi flight the morning of Sept. 9, 2012, when they saw a flock of geese approaching from the right. “The pilot-in-command believed that the birds would impact the cockpit windows, so he pushed forward on the control yoke to descend,” the NTSB report said.
The Navajo touched down hard on the runway and bounced. The pilots continued the takeoff and returned to the airport for an uneventful landing. “Postaccident examination revealed structural damage to the airframe,” the report said. “Also, bird remains were found on the fuselage.”
Rudder Trim Bolt Removed
Piper Aerostar 601P. Substantial damage. No injuries.
Shortly after taking off from Alpine, Texas, U.S., the afternoon of Aug. 22, 2011, the pilot felt a vibration in the Aerostar’s flight controls and decided to return to the airport for a precautionary landing.
The Aerostar struck a fence on short final approach and touched down hard on the runway. “During the landing, the main landing gear was pushed up through the wing and the nose gear collapsed,” the NTSB report said. “The airplane subsequently exited the runway before coming to rest in an upright position.” The pilot and his two passengers escaped injury.
Examination of the airplane revealed that the bolt attaching the rudder trim tab to the actuator connecting rod was missing. “The absence of this bolt would have allowed the trim tab to swing freely on its hinge,” the report said.
The pilot told investigators that during his preflight inspection of the airplane, he found that the rudder trim system was inoperative. “Unable to center the rudder trim tab, the pilot elected to remove the bolt before takeoff,” the report said. “The pilot further reported that he was planning to have the trim system repaired when he returned to his home base.”
Unlatched Cowling Opens
Eurocopter MBB-BK 117-C2. Substantial damage. No injuries.
The pilot was landing the EMS helicopter on a rooftop helipad at a downtown Houston hospital on July 24, 2012, when he felt a brief shudder, similar to flying through another helicopter’s rotor wash. “The pilot was unaware that any damage had occurred and landed uneventfully,” said the NTSB report.
A third medical crewmember boarded, and the helicopter was flown to a suburban hospital. After landing there, the crew found that the cowling on the left side of the engine had opened during the previous landing and had struck all four main rotor blades.
“The pilot stated that he failed to complete a thorough preflight inspection before the accident flight because the crew was assigned a medical mission just after their shift started,” the report said. “The pilot who flew the helicopter the evening before the accident stated that he had opened the cowling to check the oil level and became distracted. He could not remember if he had secured the cowling latches.”
Rotor Drag Damper Fails
Schweizer 269C. Destroyed. Two fatalities.
The pilot was repositioning the helicopter from Saint-Aignan to Breuil in France the morning of July 25, 2010, in preparation for initiation flights at an air show. About 10 minutes after takeoff, a main rotor blade drag damper failed. The pilot lost control of the helicopter, which collided with treetops and descended to the ground.
“The helicopter was being operated in the context of an aerial work company without an AOC [aircraft operating certificate],” said the report by the French Bureau d’Enquêtes et d’Analyses.
The pilot, also a certified maintenance technician, recently had performed a required 300-hour inspection of all three drag dampers and had signed them off as meeting specifications. However, he had failed to notice “degradation of the elastomer on the drag dampers,” the report said. “This maintenance operation on a critical part performed by a lone mechanic and without approval by another person or an organisation independent of the operator could have contributed to the accident