Landing (descent or approach)

The copilot inadvertently induced a lateral oscillation and lost control of the airplane while practicing touch-and-go landings. The pilot made the first touch-and-go. The copilot successfully made the second touch-and-go. The copilot attempted the third touch-and-go. At 50 feet, he disengaged the yaw damper and entered a pilot induced lateral oscillation. The airplane rapidly decelerated and developed a high sink rate. The airplane dragged the right tip fuel tank, which separated from the airplane, and the airplane bounced back into the air. The airplane landed hard, the main landing gear collapsed, and the airplane skidded to a stop off the right side of the runway. Both pilots and the passenger deplaned through the main entry door. The pilot-in-command had not demonstrated the handling characteristics of the airplane with the yaw damper off, and he felt he did not react quickly enough to prevent the accident.

While on approach to Santiago de Compostela Airport, around 0000LT, meteorological conditions were reported to be good, and the crew requested a visual approach to runway 17, even though the active runway was 35. Once cleared to land, the aircraft encountered a fog patch and from this moment it began a high rate descent (2,000 to 3,000 feet per minute). A minute after entering an unexpected and unforeseen fog patch, at 00:13:02 of June 7, the aircraft struck some trees, in level flight and with an airspeed of 148 knots. The wings and engines detached from the fuselage, and they dragged along a scrubland area until they came to a stop. The crew suffered minor injuries and the aircraft was completely destroyed.

Following an uneventful cargo flight from Guarapuava, the crew started the descent to Curitiba-Bacacheri Airport by night and adverse weather conditions. After touchdown on a wet runway surface, the twin engine aircraft went out of control, overran and collided with a concrete wall. All three occupants were injured, one of the pilot seriously.

The aircraft departed Franca Airport in the evening on a cargo flight to São Paulo, carrying one pilot and bank notes. On a night approach to São Paulo-Congonhas Airport, the pilot cancelled the IFR flight plan when he encountered technical problems with the right engine. He shut down the engine and continued the approach to runway 35R without informing ATC of his situation. Too high on the glide, he apparently decided to initiate a go-around when he lost control of the aircraft that rolled to the left, lost height and crashed in a residential area, bursting into flames. The aircraft was destroyed and the pilot was killed. Two people on the ground were injured.

About 20 minutes before the accident, the pilot reported to the air traffic controller that he had a problem with an engine and needed to shut the engine down. The flight had just leveled at 23,000 feet. The controller told the pilot that he was near Jackson, Tennessee, and that he could descend to 7,000 feet. About 10 minutes later, the pilot reported he was at 8,000 feet and requested radar vectors for the instrument landing system approach to runway 2 at the McKellar-Sipes Regional Airport, at Jackson. The pilot told the controller he had the left engine shut down. About 5 minutes later, the pilot reported he had a propeller runaway. About 1 minute later, the pilot reported he was in visual conditions and requested radar vectors direct to the airport. About 2 minutes later, the pilot reported he had a cloud layer under him and that he had the localizer frequency for runway 2 set. About 1 minute later, the pilot was told to contact the McKellar Airport control tower. The pilot acknowledged this instruction. No further transmissions were received from the flight. Examination of the left engine at the accident site showed the left propeller control was found disconnected at the point the propeller control extension bracket attaches to the propeller governor. The propeller control cable had also pulled loose from a swaged point at the control rod and was also separated further aft due to overstress. The housing for the propeller control rod was found securely attached to the engine and the control rod was securely attached to the extension bracket. The propeller governor control arm, which was disconnected from the propeller control cable and rod, was found spring loaded into the high RPM position. Examination of the fractured left propeller bracket assembly was performed by the NTSB Materials Laboratory, Washington, D.C. The bracket assembly was fractured in the area of the outermost eyehole, at the point a bolt passes through the bracket assembly and the propeller governor arm. The fracture surface contained small amounts of dirt, grease, and minor corrosion. The fracture surface features include flat areas that lie on multiple planes separated by ratchet marks, features typically left behind by the propagation of a fatigue crack. The fatigue crack emanated from multiple origins on opposite sides of the bracket. The total area of the fatigue crack occupied approximately 85 percent of the fracture surfaces. The fatigue fractures initiated on the outer edges of the surface and propagated inward toward the center. The remaining 15% of the fracture surface had features consistent with overstress separation. Near the middle of each fatigue region were microfissures suggesting that the crack propagated under high-stress conditions. The NTSB Materials Laboratory also examined the separation point between the left propeller control flexible cable and the rigid rod that connects to the bracket assembly. The cable and the swaged part of the rigid rod were in good condition with no fractures or damage. The Piper PA-31-T2 Pilot Operating Handbook, Section 3, Emergency Procedures, does not contain a procedure for loss of propeller control. Section 3 did contain a procedure for "Over speeding Propeller", which stated that if a propellers speed should exceed 1,976 rpm, to place the power lever of the engine with the over speeding propeller to idle, feather the propeller, place the engine condition lever in the stop position, and complete the engine shutdown procedures. Pilot logbook records show the pilot completed a simulator training course for the accident model airplane about 9 days before the accident and had about 13 flight hours in the Piper PA-31-T2.

The pilot departed for the cross-country flight with 10 gallons of fuel in the left tank and 17 gallons of fuel in the right tank. He leveled off and reduced to cruise power. He said he was "preparing to make switch from left to right tank....just before I could make the switch, the engine lost power." He attempted to switch tanks and restart the engine, but could not get a restart. He performed a forced landing to a dirt road. During the landing roll, the left wing struck a tree and the airplane rotated 180 degrees. The engine was torn from the mount, both wing spars were bent, and the empennage sustained substantial damage. A salvage team member noted, during the airplanes recovery, that there were approximately 10 to 15 gallons of fuel in the left tank; he said the right fuel tank was empty.

During landing touchdown, following a stabilized approach, the right main landing gear failed. The airplane remained controllable by the pilots and came to a stop on the runway, resting on its right wing. The DFW Fire Department arrived at the accident site in 35 seconds and, following communication between the airplane's Captain and Fire Department's Incident Commander, it was decided that an emergency evacuation of the airplane was not necessary. Examination revealed that the right main gear's outer cylinder had fractured allowing the lower portion of the gear (including the wheel assembly) to separate from the airplane. Research, examination & testing of the cylinder revealed that a forging fold was introduced into the material during the first stage of its forging process. The first stage is a hand operation, therefore the quality is highly dependent on the person performing the hand operation. Following the first landing, the forging fold became a surface breaking crack, due to the normal loads imposed during landing. Although growth of the fatigue crack was suppressed by crack blunting, high load landings resulted in growth of the fatigue crack. Subsequently, the landing gear failed when the crack had reached a critical length. Additionally, the airplane's maintenance records were reviewed and no anomalies were found.

First Air Flight 953, a Boeing 737-210C, serial number 21066, was on a scheduled flight from Edmonton, Alberta, to Yellowknife, Northwest Territories. On board were 2 flight crew, 4 cabin crew, and 98 passengers. The flight departed Edmonton at 1130 mountain daylight time, with an estimated time en route of 1 hour 35 minutes. As the aircraft approached Yellowknife, the spoilers were armed, and the aircraft was configured for a visual approach and landing on Runway 33. The computed Vref was 128 knots, and target speed was 133 knots. While in the landing flare, the aircraft entered a higher-than-normal sink rate, and the pilot flying (the first officer) corrected with engine power and nose-up pitch. The aircraft touched down on the main landing gear and bounced twice. While the aircraft was in the air, the captain took control and lowered the nose to minimize the bounce. The aircraft landed on its nose landing-gear, then on the main gear. The aircraft initially touched down about 1300 feet from the approach end of Runway 33. Numerous aircraft rubber scrub marks were present in this area and did not allow for an accurate measurement. During the third touchdown on the nose landing-gear, the left nose-tire burst, leaving a shimmy-like mark on the runway. The aircraft was taxied to the ramp and shut down. The aircraft was substantially damaged. There were no reported injuries to the crew or the passengers. The accident occurred at 1325, during the hours of daylight.

After about a 20 minute flight, while on final approach for landing, the airplane experienced a loss of engine power on both engines, and the pilot-in-command (PIC) performed a forced landing into trees about 1/2 mile from the airport. The left and right boost pumps and the left and right transfer pumps, were observed in the "OFF" position. According to the PIC, after he exited the airplane, he returned to the cockpit and "shut off the fuel panel. The fuel quantity indicator toggle switch was observed in the "TOTAL" position. Examination of the fuel system revealed both engine nacelle tanks, both wing center section tanks, and the right wing fuel tanks were not compromised. About 1 quart of fuel was drained from the left and right engine nacelle tanks, respectively. Less than a quart of fuel was drained from the right wing tanks. The left wing tanks were compromised during the accident; however there was and no evidence of a fuel spill. Examination of the left and right wing center tanks revealed approximately 27 gallons (approximately 181 lbs) of fuel present in each tank. Battery power was connected to the airplane, and when the fuel transfer pump switches were turned to the "ON" position, fuel was observed being pumped from the left and right wing center tanks to their respective nacelle tanks. The accident flight was the third flight of the day for the flight crew and airplane. According to a flight log located in the cockpit, the flight crew indicated 750 lbs of fuel remained at the time of the takeoff. According to the airplane flight manual (AFM),"Fuel for each engine is supplied from a nacelle tank and four interconnected wing tanks...The outboard wing tanks supply the center section wing tank by gravity flow. The nacelle tank draws its fuel supply from the center section tank. Since the center section tank is lower than the other wing tanks and the nacelle tank, the fuel is transferred to the nacelle tank by the fuel transfer pump in the low spot of the center section tank...." Additionally, with the transfer pumps inoperative, all wing fuel except 28 gallons from each wing will transfer to the nacelle tank through gravity feed.

The three engine aircraft departed Tehran-Mehrabad Airport at 0645LT on a charter flight to Gorgan, carrying members of the parliament and government who were flying to Gorgan to inaugurate the new airport. En route, the crew was informed by ATC about the deterioration of the weather conditions at destination and was instructed to divert to Sari Airport. While descending to Sari in marginal weather conditions, the crew failed to realize his altitude was too low when the aircraft struck the slope of a mountain located about 20 km south of the airport. The aircraft disintegrated on impact and all 30 occupants were killed. Among the passengers were Rahman Dadman, Iranian Minister of Transport and two vice-ministers.