Two deadly Beechcraft King Air accidents at the end of June helped propel business aviation safety into one of its darkest periods. The fact that both accidents occurred shortly after takeoff-and several recent similar events-might be cause for alarm for this popular twin turboprop.
Combined, these two crashes-one in Hawaii, the other in Texas-accounted for 21 of the 57 business aviation fatalities during the first half of 2019. That's a sixfold increase from the same period last year.
Since October 2014 there have been at least five King Air accidents during takeoff or initial climb. During each of these events, including the two most recent crashes, the pilot lost control of the aircraft shortly after takeoff. In four of these events, the aircraft wreckage hit structures on or near an airport.
Earlier this month, the NTSB released preliminary reports on the two most recent crashes. Each report provides information related to each event and signifies the beginning of an extensive investigation to determine probable cause; the more conclusive final reports are typically published within 12 months of an accident.
In the first of the two fatal King Air accidents this year, a King Air A90 collided with terrain after takeoff from Dillingham Airfield in Mokuleia, Hawaii. A commercial-rated pilot and 10 passengers were killed on this local skydiving flight.
According to the preliminary report, a witness (employed by the operator) stated he could hear "the engines during the initial ground roll and stated the engines sounded normal, consistent with the engines operating at high power." He then observed the aircraft at an altitude between 150 and 200 feet above ground level. It appeared to be turning and he could see the belly of the airplane and the cabin facing the ocean to the north.
Shortly afterward, the aircraft "struck the ground in a nose-down attitude, and a fireball erupted." The report continued that a preliminary review of video from an airport surveillance camera revealed "that just before impact, the airplane was in an inverted 45-degree nose-down attitude."
On June 30, nine days after the Hawaii crash, a King Air 350 collided with a hangar and terrain after takeoff from Addison Airport in Texas. Two pilots, one an ATP and the other commercial-rated, and eight passengers died. The Part 91 cross-country flight was planned to depart Addison and fly to St. Petersburg, Florida.
The NTSB is investigating the June 31 tragedy, which killed eight passengers and two crewmembers.
According to the preliminary report, the takeoff and departure of the airplane were captured by several video cameras and radar and observed by witnesses. One witness stated that as the aircraft went down the runway, "it seemed quieter than normal and sounded like it didn't have sufficient power to takeoff."
After takeoff, witnesses observed the airplane drift to the left and then roll to the left before colliding with the hangar. The report added that several security cameras captured the drift to the left after takeoff and "one camera showed the airplane roll completely inverted before it collided with the hangar." The aircraft was equipped with a cockpit voice recorder. The report stated that eight seconds before the end of the recording, a crewmember commented on a problem with the left engine. Three seconds before the end of the recording, three automated "bank angle" aural alerts were recorded.
Final reports have been published on the other three takeoff events involving King Airs-two in the U.S., the other in Australia. Examining each of these past events might provide some hints of what happened in the most recent events. Of interest: in each of these earlier cases, investigators cited pilot performance as an issue rather than aircraft performance.
On Oct. 30, 2014, a King Air B200 crashed into a FlightSafety International (FSI) simulator building at Wichita Eisenhower Airport (KICT). The ATP-rated pilot was killed along with three people in the FSI facility; two others on the ground received serious injuries. This flight was planned as a Part 91 repositioning flight from KICT to Mena, Arkansas.
During takeoff, the pilot declared an emergency and stated that the airplane "lost the left engine." According to the report, the aircraft climbed to about 120 feet above ground with its landing gear extended, continued a left turn, and descended into the building.
Post-accident examination did not identify any anomalies with the airplane, engines, or propellers that would prevent normal operation. It was determined that the left engine was developing low to moderate power while the right engine was developing moderate to high power. Neither propeller was feathered.
A "sideslip thrust and rudder study" completed by the NTSB determined that during the last second of flight, the airplane had a nose-left side slip of 29 degrees. The report concluded that the pilot likely applied substantial "inappropriate" left rudder input (remember the pilot reported a "lost" left engine) and failed to maintain lateral control of the airplane. Other contributing factors included the pilot's failure to follow emergency procedures-including feathering the propeller and retracting the landing gear-for an engine failure.
On Jan. 23, 2017, a King Air 300 crashed shortly after takeoff in Tucson, Arizona. The ATP-rated pilot and a passenger were fatally injured. According to the NTSB final report, after takeoff the aircraft "reached an altitude of about 100 to 150 feet above the runway in a nose-high pitch attitude, the airplane rolled left to an inverted position as its nose dropped, and it descended to terrain impact on the airport (coming to rest against a concrete wall), consistent with an aerodynamic stall."
Post-accident examination of the aircraft found no evidence of preexisting anomalies that would preclude normal operations. However, post-accident toxicology testing of the pilot revealed the use of multiple psychoactive substances that included over-the-counter, prescription, and illicit drugs. The NTSB determined probable cause as "the pilot's exceedance of the airplane's critical angle of attack during takeoff, which resulted in aerodynamic stall. Contributing to the accident was the pilot's impairment by the effects of a combination of psychoactive substances."
On Feb. 21, 2017, a King Air B200 crashed into a shopping mall seconds after taking off from Essendon Airport in Melbourne, Australia. The charter flight was scheduled to carry four American passengers to King Island to play golf; all five people on board, including the Australian pilot, were killed in the crash. An investigation by the Australian Transport Safety Board (ATSB) determined that the accident was the result of a flight control trim tab being set incorrectly before takeoff.
The ATSB could not identify any preexisting faults with the aircraft. Investigators determined that the mis-set rudder trim caused a longer takeoff roll and that once the airplane was airborne, this caused it to slip and yaw to the left. After takeoff, the pilot made two "mayday" calls and falsely identified the issue as an engine failure.
During the investigation, the ATSB also determined that the aircraft was above its maximum allowable takeoff weight during the takeoff but did not cite this weight discrepancy as a contributing factor.
Analysis of recent and past King Air accidents during takeoff and initial climb suggest that each event is unique. All three accidents examined that have a final report published identify specific pilot actions-use of the wrong rudder, loss of control due to impairment, or a mis-set trim-as probable causes and none identify any mechanical issues with the aircraft.
These pilot actions (other than the impaired pilot) can be mitigated through better training or employing safeguards (such as checklists) to ensure that items such as the trim is properly set. Not mentioned in either of the final reports was the fact that these aircraft were flown single-pilot; of all the accidents-only the Addison one had a pilot in the right seat.
A lack of familiarity or experience with an aircraft might have contributed to one recent (Addison) and two past accidents (Wichita and Tucson); those events involved either newly purchased aircraft or a "ferry" flight by a contract pilot. In the past, the insurance industry has served as the "de facto" regulator and has mandated minimum flight experience, recency, or proficiency in type.
Following the most recent King Air accidents, there will be a lot of interest when the NTSB publishes the respective final reports. From this brief analysis, the airframe, engines, and propellers appear to be sound (7,500 examples have been flying since the 1960s), but more intense scrutiny on the operators and pilots (training, qualifications, and so on) might be in order.
Ingen kommentarer:
Legg inn en kommentar
Merk: Bare medlemmer av denne bloggen kan legge inn en kommentar.