Thursday, January 1, 2004
Take A Good Look
Step back during the preflight and make sure the controls are in line
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.
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