Back when I was a student pilot, I developed a habit during the preflight inspection of stepping back and pausing to get an overall visual impression of the control surfaces on the airplane. It started after I had noticed that one of the ailerons on a Cherokee I was about to take out for a solo flight didn’t look quite right. From a distance, it was easy to see that while the aileron on one side was in alignment, the other aileron was sagging significantly.
My little habit was vindicated recently when the National Transportation Safety Board added its considerable weight to the notion that DC-8 flight crews need to get a good visual impression of elevator control surface positions during walkaround inspections. This was an outgrowth of its investigation into the February 16, 2000, crash of a four-engine DC-8 cargo jet. Misalignment of the left and right elevator and control tab surfaces with respect to one another might have been spotted during the walkaround inspection, preventing the accident.
Emery Worldwide Airlines’ flight 17 crashed in an automobile salvage yard shortly after takeoff while attempting to return to Sacramento Mather Airport (MHR), Rancho Cordova, Calif. It was operating under Part 121 as a scheduled cargo flight from MHR to Dayton International Airport (DAY), Dayton, Ohio. The three flight crewmembers were killed and the airplane was destroyed. Night visual meteorological conditions prevailed for the flight, which operated on an IFR flight plan.
Post-accident interviews indicated that while cargo-handling personnel were loading the airplane at MHR, the flight engineer conducted a preflight inspection of the exterior of the accident airplane. Ground personnel set up light stands along the left side of the airplane, but there was no significant direct light on the right side.
The cargo-loading supervisor received a copy of the signed load planning sheet and the completed weight and balance form from the pilots just before the airplane’s doors were closed for departure. There were no anomalies or irregularities with the paperwork or procedures.
According to the cockpit voice recorder (CVR), about 7:42:31, the flight crew began the taxi checklist. About 7:42:43, the flight engineer stated, “Controls, EPI.” The first officer responded, “Checked,” and the flight engineer repeated, “Checked.” Flight data recorder (FDR) data indicates that, during the elevator control check, the accident airplane’s control column moved from 10.8 degrees forward of its vertical position to 17.3 degrees forward of vertical.
During this time, the FDR recorded the elevator surfaces moving from 16.6 degrees trailing edge up (TEU) to 2.8 degrees TEU. No trailing edge down (TED) deflection was recorded during this elevator check.
About 7:43:23, the flight engineer indicated that the taxi checklist was complete. At about 7:49:06, the airplane reached rotation speed of about 146 knots. Information from the FDR confirmed that the airplane pitched from 0.2 degrees “aircraft nose up” (ANU) to 5.3 degrees ANU in about two seconds. The pitch continued to increase despite the forward movement of the control column. About 7:49:08, the CVR began to record a sound similar to the airplane’s stabilizer trim-in-motion alert, which continued to sound as the captain stated, “Watch the tail,” about 7:49:09. By 7:49:12, the airplane’s pitch had increased to 11.7 degrees nose up.
By 7:49:15, the airplane’s pitch had increased to 18.3 degrees ANU and the control column position was at 16.2 degrees forward of vertical.
FDR data indicated that the aircraft entered a left turn that steepened to about 35 degrees within about 10 seconds, almost immediately after it lifted off.
About 7:49:19, the CVR recorded the first officer stating, “We’re going back—CG’s way [sic] out of limits.”
Two seconds later, the CVR recorded a sound similar to decreasing engine rpm, followed by a sound similar to the airplane’s stall warning stick-shaker.
About 7:49:36, the CVR recorded the captain advising Sacramento TRACON that the flight had an emergency. About 7:49:40, the CVR recorded the first officer stating, “You steer. I’m pushing,” while Sacramento TRACON asked the pilots to repeat their radio message.
At 7:49:46, the CVR recorded a sound similar to increased engine rpm, followed almost immediately by the ground proximity warning system’s (GPWS) “whoop, whoop, pull up” audible alert and the first officer’s call for “Power.” According to FDR data, at this time the airplane was descending through 679 feet MSL in a steepening left bank of about 11 degrees. The recorded control column position was about 14 degrees forward of vertical and the elevator surface deflection was about 10 degrees TEU. FDR data showed that the airplane continued to descend until about 7:49:50, when it reached about 601 feet MSL and began to climb again.
About 7:49:52, as the airplane climbed through 625 feet MSL, the GPWS audible alert ceased and the captain stated, “All right, all right—all right.”
About 7:49:54, as the airplane climbed through 673 feet MSL, the first officer stated, “Push” and the flight engineer stated, “Okay, so, we’re going back up.”
As the airplane’s altitude was increasing, its left bank also increased, reaching about 45 degrees between 7:49:55 and 7:49:56, then began to decrease.
About 7:49:57, the CVR recorded the flight engineer stating, “There you go,” then the captain stating, “Roll out,” followed by an unidentified crewmember saying, “Roll out” and the sound of a strained exhale.
About 7:50:10, as the airplane was rolling out of its left bank on a heading of about 022 degrees, the CVR recorded the sound of another strained exhale.
About 7:50:11, the flight engineer asked, “Anything I can do, guys?” and the captain stated, “Roll out to the right.”
About 7:50:12, the CVR recorded the first officer stating, “Okay, push.” For the next four seconds, the airplane continued to fly on a north-northeasterly heading, approximately parallel to the departure runway at an altitude of about 1,000 feet MSL. About 7:50:16, the CVR recorded a crewmember stating, “Push forward.”
During the next 10 seconds, the airplane banked right to an east-northeasterly heading, then climbed, reaching 1,087 feet MSL (the maximum altitude obtained for the accident flight) at about 7:50:18, before it began to descend again. From 7:50:29 to about 7:50:35, as the airplane’s right bank decreased, the GPWS audible alert sounded again. Between 7:50:33 and 7:50:34, the airplane transitioned from a right bank into a left bank.
About 7:50:37, the first officer stated, “What I’m trying to do is make the airplane’s pitch match the elevator. That’s why I’m putting it in a bank.”
About 7:50:45, the captain replied, “All right, left turn” and, about 7:50:46, the first officer added, “So we’re gonna have to land it in a turn.”
About 7:50:54, the first officer asked, “You got the airport?” At 7:51:00, the first officer requested more power. Two seconds later, the CVR recorded the GPWS audible alert again briefly. According to FDR data, at about 7:51:03, the accident airplane was at an altitude of 430 feet MSL in a 24-degree left bank, passing through a heading of about 325. Two seconds later, the airplane was at 423 feet MSL in a 28-degree left bank, passing through a heading of 312. At 7:51:07, the CVR recorded the first officer stating, “Power, aww [expletive].” One second later, at 7:51:08, the CVR recorded a sound similar to impact.
The Safety Board’s examination of the airplane wreckage revealed that the bolt that usually attaches the right elevator control tab crank fitting to its pushrod was missing. This bolt and its attaching hardware weren’t recovered.
The NTSB determined the probable cause of the accident was a loss of pitch control resulting from the disconnection of the right elevator control tab. The disconnection was caused by the maintenance failure to properly secure and inspect the attachment bolt.