Nashville-Intl

The crew was completing a positioning flight from Nashville International Airport. After landing on runway 32 at Monmouth Airport, the crew started the braking procedure when the airplane deviated from the runway centerline to the left. It veered off runway to the left, crossed the parallel taxiway, lost its left main gain and nose gear and eventually came to rest perpendicular to the runway. Both pilots escaped uninjured. Referring to the photos, it appears that only the left reverser deployed.

On December 15, 2015, at 5:23pm central standard time (CST), Southwest Airlines flight 31, a Boeing 737-300, N649SW, exited the taxiway while taxing to the gate and came to rest in a ditch at the Nashville International Airport (BNA), Nashville, Tennessee. Nine of the 138 passengers and crew onboard received minor injuries during the evacuation and the airplane was substantially damaged. The airplane was operating under the provisions of 14 Code of Federal Regulations Part 121 as a regularly scheduled passenger flight from William P. Hobby Airport (HOU), Houston, Texas. Weather was not a factor, light conditions were dark just after sunset. The airplane landed normally on runway 20R and exited at taxiway B2. The flight crew received and understood the taxi instructions to their assigned gate. As the crew proceeded along taxiway T3, the flight crew had difficulty locating taxiway T4 as the area was dark, and there was glare from the terminal lights ahead. The crew maneuvered the airplane along T3 and onto T4, and then turned back to the right on a general heading consistent with heading across the ramp toward the assigned gate. The flight crew could not see T4 or the grassy area because the taxiway lights were off and the glare from the terminal lights. As a result, the airplane left the pavement and came to rest in a drainage ditch resulting in substantial damage to airplane. The cabin crew initially attempted to keep the passengers seated, but after being unable to contact the flight crew due to the loud alarm on the flight deck, the cabin crew properly initiated and conducted an evacuation. As a result of past complaints regarding the brightness of the green taxiway centerline lights on taxiways H, J, L and T-6, BNA tower controllers routinely turned off the taxiway centerline lighting. Although the facility had not received any requests on the day of the accident, about 30 minutes prior to the event the tower controller in charge (CIC) turned off the centerline lights as a matter of routine. In doing so, the CIC inadvertently turned off the "TWY J & Apron 2" selector, which included the taxiway lights in the vicinity of the excursion. The airfield lighting panel screensaver feature prevented the tower controllers from having an immediate visual reference to the status of the airfield lighting.

As the airplane was on final approach, the captain, who was the pilot monitoring (PM), realized that the flaps were not configured as had been briefed, with a setting of 40 degrees for the landing. Data from the flight data recorder (FDR) indicate that the captain set the flaps to 40 degrees as the airplane was descending through about 500 ft altitude, which was about 51 seconds from touchdown. When the airplane was between 100 to 200 ft altitude, it was above the glideslope. Concerned that the airplane was too high, the captain exclaimed repeatedly "get down" to the first officer about 9 seconds from touchdown. About 3 seconds from touchdown when the airplane was about 27 ft altitude, the captain announced "I got it," indicating that she was taking control of the airplane, and the first officer replied, "ok, you got it." According to FDR data, after the captain took control, the control column was relaxed to a neutral position and the throttles were not advanced until about 1 second before touchdown. The airplane touched down at a descent rate of 960 ft per minute and a nose-down pitch attitude of -3.1 degrees, resulting in the nose gear contacting the runway first and a hard landing. The airplane came to a stop on the right side of the runway centerline about 2,500 ft from its initial touchdown. The operator's stabilized approach criteria require an immediate go-around if the airplane flaps or landing gear were not in the final landing configuration by 1,000 ft above the touchdown zone; in this case, the flaps were not correctly configured until the airplane was passing through 500 ft. Further, the airplane's deviation about the glideslope at 100 to 200 ft would have been another opportunity for the captain, as the PM at this point during the flight, to call for a go-around, as indicated in the Southwest Airlines Flight Operations Manual (FOM). Accident data suggest that pilots often fail to perform a go-around or missed approach when stabilized approach criteria are not met. A review of NTSB investigated accidents by human factors researchers found that about 75% of accidents were the result of plan continuation errors in which the crew continued an approach despite cues that suggested it should not be continued. Additionally, line operations safety audit data presented at the International Air Safety Summit in 2011 suggested that 97% of unstabilized approaches were continued to landing even though doing so was in violation of companies' standard operating procedures (SOPs). The Southwest FOM also states that the captain can take control of the airplane for safety reasons; however, the captain's decision to take control of the airplane at 27 ft above the ground did not allow her adequate time to correct the airplane's deteriorating energy state and prevent the nose landing gear from striking the runway. The late transfer of control resulted in neither pilot being able to effectively monitor the airplane's altitude and attitude. The first officer reported that, after the captain took control of the airplane, he scanned the altimeter and airspeed to gain situational awareness but that he became distracted by the runway "rushing" up to them and "there was no time to say anything." The captain should have called for a go-around when it was apparent that the approach was unstabilized well before the point that she attempted to salvage the landing by taking control of the airplane at a very low altitude. In addition, the captain did not follow SOPs at several points during the flight. As PM, she should have made the standard callout per the Southwest FOM when the airplane was above glideslope, stating "glideslope" and adding a descriptive word or words to the callout (for example, "one dot high"). Rather than make this callout, however, the captain repeatedly said "get down" to the first officer before stating "I got it." The way she handled the transfer of airplane control was also contrary to the FOM, which indicates that the PM should say "I have the aircraft." The flight crew's performance was indicative of poor crew resource management.

The multiengine airplane was at an altitude of 6,000 feet when it experienced a catastrophic right engine failure, approximately 15 minutes after takeoff. The pilot elected to return to his departure airport, which was 30 miles away, instead of diverting to a suitable airport that was located about 10 miles away. The pilot reported that he was not able to maintain altitude and the airplane descended until it struck trees and impacted the ground, approximately 3 miles from the departure airport. The majority of the wreckage was consumed by fire. A 5 1/2 by 6-inch hole was observed in the top right portion of the crankcase. Examination of the right engine revealed that the No. 2 cylinder separated from the crankcase in flight. Two No. 2 cylinder studs were found to have fatigue fractures consistent with insufficient preload on their respective bolts. In addition, a fatigue fracture was observed on a portion of the right side of the crankcase, mostly perpendicular to the threaded bore of the cylinder stud. The rear top 3/8-inch and the front top 1/2-inch cylinder hold-down studs for the No. 2 cylinder exceeded the manufacturer's specified length from the case deck by .085 and .111 inches, respectively. The airplane had been operated for about 50 hours since its most recent annual inspection, which was performed about 8 months prior the accident. The right engine had been operated for about 1,425 hours since it was overhauled, and about 455 hours since the No. 2 cylinder was removed for the replacement of six cylinder studs. It was not clear why the pilot was unable to maintain altitude after the right engine failure; however, the airplane was easily capable of reaching an alternate airport had the pilot elected not to return to his departure airport.

While in cruise flight at 24,000 feet msl, the pilot of the Piper Malibu Mirage advised Memphis Center that he had encountered icing conditions and was experiencing a fuel imbalance. The pilot requested and was cleared to deviate to the north. Subsequently, radio and radar contact were lost. A witness reported hearing the sound of the airplane's engine stop running and observed the airplane descending from the dark clouds in a nose down attitude and rotating clockwise. Residents of the area reported that the weather at the time of the accident was high ceilings with heavy rain just before and after the accident. There were thunderstorms with lightning in the area at the time of the accident. The wreckage of the airplane was scattered along an area of about four miles. The airplane was equipped with an autopilot, weather radar, and an ice protection system. The pilot had recently purchased the 1999 model airplane and had completed a Mirage initial training course. At the time of the accident the pilot had accumulated a total of 21.4 hours in the make and model of the accident aircraft. No anomalies were found with the airframe or engine that would have prevented normal operation.

During flight, the airplane was cruising at flight level 210 in IFR conditions with turbulence and with the wind from about 255 degrees at 70 knots. The airplane drifted off course at about 1600 cst. At 1610:09, after about ten minutes of unrecognized heading changes, the pilot stated '. . . I've lost my gyro.' At 1610:15, the controller issued a no-gyro vector. At 1611:29, as the airplane was still turning (to a heading that would intercept the original course), the pilot stated 'we've lost aLL our instruments . . . please direct me towards VFR.' He was cleared to descend to 14,000 feet. At about that same time, he stated 'we're in trouble' and 'we've lost all vacuum,' then there was no further radio transmission from the airplane. The airplane entered a steep, downward spiraling, right turn. The left outer wing panel separated up and aft (in flight) from overload and impacted the left stabilizer. The airplane crashed, and parts that separated from the airplane were found over a four mile area. Investigation revealed evidence that the HSI heading card can fail without the HDG flag appearing. Although the pilot had reported the loss of instruments and vacuum, examination of the airplane revealed that the engine, flight controls, electrical system, pitot/static system and vacuum systems exhibited continuity. No malfunction was found that would have led to loss of pressurization or hypoxia.

The aircraft was being operated as general aviation flight 115 and was departing on a routine night flight. During takeoff/initial climb, the left engine lost power. The flight crew attempted to control the climb-out, but following the application of water-methanol, the pilot lost directional control. Subsequently, the aircraft banked to the left, entered a descent and impacted between the parallel runway. An investigation disclosed that the left propeller's blade angle was 21°. No preimpact system malfunction or failure was found. The cockpit voice recording indicated that the flight crew did not complete all of the items on the before taxi/takeoff checklist. One of the items (presumably not completed) was a check of the h.p. cock levers. The checklist required that the h.p. cock levers be in 'cruise lockout' for takeoff. The left h.p. cock lever was found between the 'fuel off' and 'feather' positions. Movement to this position would have deactivated the auto-feather sys and shut down the left engine. Both pilots were killed.