DCA22MA009

The jammed condition of both elevators, which resulted from exposure to localized, dynamic high wind while the airplane was parked and prevented the airplane from rotating during the takeoff roll. Also causal was the failure of Everts Air Cargo, the pilots’ primary employer, to maintain awareness of Boeing-issued, required updates for its manuals, which resulted in the pilots not receiving the procedures and training that addressed the requirement to visually verify during the preflight checks that the elevators are not jammed.

Accident Sequence The captain (who was the pilot flying) initiated the takeoff roll, and the airplane accelerated normally. According to the cockpit voice recorder (CVR) transcript, the first officer made the “V1” and then “rotate” callouts. According to the captain (in a postaccident interview), when he pulled back on the control column to rotate the airplane, “nothing happened,” and the control column felt like it “was in concrete” and “frozen.” The CVR captured that the first officer subsequently made the “V2” callout, then the captain said “come on” in a strained voice. Both pilots recalled in postaccident interviews that they both attempted to pull back on the controls, but the airplane did not rotate. The CVR captured that the first officer called out “abort.” The first officer pulled the thrust levers to idle and applied the brakes, and the captain deployed the thrust reversers. (See “Execution of Rejected Takeoff” for more information.) The airplane overran the departure end of the runway and continued through the airport perimeter fence and across a road, striking electrical distribution lines and trees before coming to rest in a pasture, where a postcrash fire ensued. The pilots, two additional crewmembers, and all passengers evacuated the airplane. Two passengers received serious injuries, and one received a minor injury. (See “Emergency Evacuation” for more information.) Postaccident examination of the airplane and the related flight data recorder (FDR) data revealed no evidence of preimpact malfunction of the engines or thrust reversers that would have precluded their normal operation. Examination of the elevators and a review of FDR data for elevator position determined that both elevators were jammed trailing-edge-down, which prevented the airplane from rotating during the takeoff roll. Jammed Elevator Condition The investigation determined that, at some point during the 6 months since the airplane was last flown, the inboard geared tab linkages for both elevators had moved beyond their normal range of travel into an overcenter position, resulting in the jammed condition of the elevators in the trailing-edge-down position. No evidence of any other mechanical malfunction, elevator or pitch control system failure, structural failure, or actions by the flight crew or maintenance personnel was identified that could have resulted in the jammed condition. Further, the jammed condition was not detectable during the flight control check the first officer performed during taxi; the elevator control system design is such that, even with this type of jammed elevator condition, the control column feel and travel would be normal during taxi (when the aerodynamic forces on the elevator control tabs would be minimal). Since the airplane was last flown, it was parked outside at the departure airport and exposed to two significant high-wind events: the passage of a squall line about 5 months before the accident (with gusts to 46 kts reported at the airport) and a tropical storm about 1 month before the accident (with gusts of 35 to 45 kts reported over a 5hour period). The possibility of elevator jamming on DC-9/MD-80 series airplanes as a result of exposure to certain high-wind conditions while parked is known and evidenced by two previous events – a rejected takeoff event in 1999 in Germany and a runway overrun accident in 2017 in Ypsilanti, Michigan. The NTSB’s investigation of the Ypsilanti accident determined that the airplane’s right elevator became jammed. Although The Boeing Company (the type certificate holder for the airplane) indicated that the MD-80 series airplane was designed to withstand a 65-kt horizontal ground gust from any direction while parked or taxiing, the jamming occurred even though the highest reported wind gust was 55 kts during the time that the airplane was parked. The investigation included a wind simulation study that determined that the airflow at that airplane’s parked location was affected by the presence of a large hangar (located upwind of the airplane) that generated localized turbulence with a dynamic, vertical component. Based on the wind simulation information, the NTSB developed an elevator test plan that determined that the vertical gust loads at the Ypsilanti accident airplane’s parked location were sufficient to enable the inboard geared tab linkages for the right elevator to move into an overcenter position and jam the right elevator. The investigation found that the airworthiness standard for transport-category airplanes specified that the airplanes must be designed for the limit loads generated when subjected to a 65-kt horizonal ground gust; however, the version of the standard that applied to MD-80 series airplanes allowed for the assumption of only static loads and did not require consideration of dynamic, vertical wind components. (In 2019, the NTSB issued a safety recommendation to the Federal Aviation Administration [FAA] related to the standard. See “Previously Issued Safety Recommendations” for more information.) The accident airplane (like the Ypsilanti accident airplane) had been parked near a hangar. Although the highest reported gust or sustained wind at the airport never exceeded 46 kts while the accident airplane was parked, the localized wind conditions in the immediate vicinity of the parked airplane may have differed from the wind conditions detected by the nearest weather sensor in speed or dynamic characteristics, or both. The presence of localized differences is further supported by the fact that another DC-9 (MD-87) airplane that was parked on the ramp near the accident airplane since the accident airplane had last flown did not sustain jammed elevators. Thus, the accident airplane’s jammed elevators resulted from the airplane’s exposure to high-wind conditions while parked, which likely included localized turbulence with a vertical component. Flight Crew Procedures and Training for Exterior Inspections of Elevators In 2019, the NTSB issued Safety Recommendation A-19-2 (as a result of its investigation of the Ypsilanti accident), which recommended that Boeing develop new preflight procedures or other mitigations for DC-9/MD-80 series airplanes that will enable a flight crew to verify before takeoff that the elevators are not jammed. In response to this recommendation, in 2020, Boeing published Operations Bulletin 80-2-017, “ELEVATORS NOT JAMMED VERIFICATION” and Temporary Revision 80-2-153 to the MD 80 Flight Crew Operating Manual (FCOM), both of which included a warning stating that, before every flight, the flight crew must confirm that the elevator surfaces are not jammed in the trailing-edge-down position. According to the warning, which was added as an update to the FCOM’s Exterior Inspection Procedures, confirmation involves visually verifying that the elevators are faired (even) with or above the stabilizer surface. This flight crew verification applied to every flight, regardless of the airplane’s ground wind exposure. The bulletin also explained that, for the previous known jammed elevator events, the control column feel and travel were normal during the control checks the crews performed during taxi. As a result of Boeing’s publication of this bulletin and revised procedures, the NTSB classified Safety Recommendation A-19-2 Closed—Acceptable Action. During postaccident interviews, the captain and the first officer indicated that they were unaware of the elevator inspection procedure. Although both elevators were visibly trailing-edge-down when the first officer performed a preflight inspection of the airplane (as was evident in a photograph he took of the airplane that morning), he did not recognize the condition as anomalous. Although the flight crew accepted the 14 CFR Part 91 accident flight as contract work for the operator, 987 Investments LLC, they were trained by and used the ai

At the time of the accident, The Boeing Company held the type certificate for the DC-9-87 (MD-87) airplane (generally referred to as a DC-9/MD-80 series airplanes). The owner of 987 Investments purchased the accident airplane in 2015 and maintained it based on Boeing maintenance planning document ME80-020-TNK, dated August 1, 2019. According to the maintenance manager, maintenance checks and inspections to maintain airworthiness were accomplished since the airplane was last flown in April 2021. According to the mechanic, on the day of the accident, he completed a 72-hour service check and daily walk-around tasks, which included checking the security and condition of the airplane’s exterior, including the vertical and horizontal stabilizer surfaces. Cabin Configuration The accident airplane was originally delivered with a commercial cabin configuration, but maintenance records showed that it was modified in 2008 under an STC that specified 19 passenger seating positions (with 1 additional state room seat subject to a limitation that prohibited occupancy during taxi, takeoff, and landing). The accident airplane’s cockpit had seats for the captain and the first officer and included one retractable observer’s seat (which was unoccupied during the accident flight). According to interviews with the airplane’s owner and multiple passengers, the cabin had 22 passenger seats, each of which was equipped with a lift-latch lap belt. The owner said he was unaware that the cabin configuration differed from that specified in the STC. Elevator System The DC-9-87 (MD-87) airplane has a T-tail design, such that the elevators and horizontal stabilizer are attached near the top of the vertical stabilizer about 30 ft above ground level (agl). The left and right elevators are attached by hinges to the rear spar of the horizontal stabilizer, and each is equipped with control, geared, and antifloat tabs attached to the trailing edge (see figure 1). Figure 1. Exemplar airplane (viewed from the ground looking up) showing respective locations of right horizontal stabilizer, elevator, control tab, geared tab, and antifloat tab. (Source: Boeing) Generally, elevator control is accomplished via the elevator control tabs, which are mechanically connected to and directly controlled by the cockpit control columns. During takeoff (at Vr or higher), when a pilot provides aft control column input to command rotation, the control tabs mechanically deflect in response to the control column inputs, and the resultant aerodynamic forces on the deflected control tabs move the elevators to produce the change in airplane pitch. Elevator geared tabs, which mechanically deflect in response to elevator movements, are attached to the horizontal stabilizer through a system of drive linkages. The geared tab drive linkage consists of a pushrod that is attached to the horizontal stabilizer spar by means of an actuating crank and links (see figure 2). Figure 2. Installed location of geared tab linkage components (left) and closer view of the links and actuating crank (right). (Source: Boeing; some labels and revisions added by NTSB) The antifloat tabs (which prevent down-float of the elevator) are mechanically connected to the horizontal stabilizer, and their positions are driven by the stabilizer position. When the airplane is parked, each elevator is free to move independently within the confines of the mechanical stops if acted upon by an external force, such as wind. The elevator system (by design) has no gust lock. Automatic Spoiler System The accident airplane was equipped with an automatic spoiler system designed to automatically deploy to reduce lift and increase drag for more effective braking whenever reverse thrust is commanded. The system, which is electrically controlled and hydraulically actuated, becomes armed when a flight crewmember sets the speed brake handle before takeoff. In the event of a rejected takeoff, when a crewmember raises the thrust levers to the reverse thrust position, electrical signals are sent to the automatic spoiler actuator, which pushes the speed brake handle to its full extension, simultaneously actuating the spoilers on each wing. Owner/Operator Information The owner and operator of the airplane, 987 Investments LLC, was a privately held company that contracted with the maintenance manager, mechanics, and current and qualified pilots to operate the airplane, which the company acquired about 6 or 7 years before the accident. According to the owner, he paid a fee to Everts Air Cargo to provide the maintenance manager with information on the items due for the airplane, such as periodic inspections and airworthiness directives. The maintenance manager said that he had been overseeing the maintenance on the accident airplane for about 5 years. He said that the airplane was maintained under the Boeing maintenance program and that Everts would send him maintenance information weekly that detailed any work that needed to be done and when it was due. For the accident flight, the maintenance manager contacted Everts to inquire about a crew for the upcoming planned flight. For such requests, Everts’ director of operations would check to see which pilots were off duty on the requested days and ask them if they wanted to conduct the flight; if the pilots agreed, the director of operations would provide their contact information to the representative of 987 Investments so they could arrange the logistics. According to records maintained by the FAA’s Houston Flight Standards District Office, in September 2017, an Everts representative submitted an e-mail request to the office to operate the accident airplane under Part 91 with Everts’ pilots who were pilot-in-command-qualified. Captain At the time of the accident, the captain worked for Everts as a simulator instructor and check airman. He previously worked as Everts’ chief pilot in the DC-9/MD-80 series airplanes for about 2.5 years until he turned 65 and was no longer eligible to fly under Part 121 regulations. The captain’s most recent Part 121 training events at Everts included recurrent ground and flight training in October and November 2020, respectively, a requalification proficiency check in June 2021, and emergency procedures training in October 2021. The captain resided in Las Vegas, Nevada. On October 16, 2021 (3 days before the accident), he was in Fairbanks, Alaska, and awoke about 0515 Alaska daylight time (AKDT) for a 0700 AKDT flight home, where he arrived about 1830 Pacific daylight time (PDT). He did not nap during the day, and he went to bed about 2130 PDT. The next day, he awoke between about 0600 and 0700 PDT, did routine personal errands throughout the day, and went to bed about 2200 PDT. The day before the accident, he awoke about 0630 PDT and had a 1000 PDT flight to Houston, where he arrived about 1530. He met the first officer for dinner, went back to the hotel to watch a football game, and went to bed about 2230 to 2245. On the day of the accident, he awoke about 0630, had breakfast, and arrived at the airport about 0800 The captain said he had no problems falling asleep at night and felt rested the morning of the accident. In the 72 hours preceding the accident, the captain did not consume any alcohol or other drugs, including prescription or nonprescription medications, that might have affected his performance. He had no major changes in his personal life, finances, or health in the previous 12 months. Toxicology testing performed by the FAA’s Forensic Sciences Laboratory on the captain’s blood identified no evidence of impairing drugs. First Officer The first officer worked for Everts since June 2019. Previous employment included flying corporate airplanes for several years in the United States and overseas. The first officer’s most recent Part 121 training events at Everts included recurrent ground and flight training in January