LAX03IA098

The airplane unexpectedly rolled to the left during the climb to cruise. The takeoff and initial area departure phases were normal. The captain engaged the autopilot at 3,000 feet mean sea level (msl). Passing 8,900 feet msl, the airplane experienced a sudden upset resulting in a rapid roll of 35 degrees to the left. The captain countered with 50 to 60 degrees of right aileron input. The autopilot had been engaged, but disengaged automatically during the pilot control input. The first officer (FO) asked the captain if he wanted some aileron trim. The captain responded that he desired only a small amount, reasoning that he did not want to mask a major problem. He did not feel any vibration, binding, or unusual control feel other than the effort and aileron input required to hold wings level. He remembered seeing the right aileron and right elevator deflected upward on the Configuration synoptic page on the systems display, and thought that the aileron deflection would be consistent with his control input to lower the right wing against a left rolling tendency. He flew the airplane to a landing with approximately 45 degrees yoke deflection required to maintain a level wing attitude. Analysis of the digital flight data recorder (DFDR) data indicated that the aileron trim value was 90 percent of full aileron trim authority prior to pushback, engine start, taxi, and takeoff. The data from the previous inbound flight, which had the same flight crew showed that the trim changed from 10 to 90 percent authority about 3 minutes after the previous flight landed. The trim again shifted following the landing and taxi back of the event flight from 85 percent to 10 percent. The captain said that he felt that the airplane was not tracking properly after takeoff. The airline's debrief of the flight crew indicated that they did not see or recognize the excessive aileron deflection on the cockpit screens before or after the event worsened and resulted in autopilot disengagement. The autopilot was trying to roll out of a turn, and was commanding aileron in a direction opposite to the trim position, which resulted in the aileron torque limiter reducing the aileron authority. With the reduced authority, the aileron position could not keep up with the autopilot command, which triggered a autopilot disconnect. The airline indicated that the Rudder and Aileron check for zero is done during the Cockpit Preparation Checklist, which a crew accomplishes just prior to the Before Starting Engines Checklist. DFDR data about 2/3 of the way through the flight indicated that the trim did respond when the copilot manipulated it. The data also showed that the trim repositioned back to zero at the end of the flight. Thorough post accident tests of the system found that the aileron trim control switches and the aileron trim control actuator unit functioned per design specifications with no mechanical or circuit discrepancies noted. Testing demonstrated that there was no evidence of any uncommanded motion. Tests were also performed on the Aileron and Rudder Trim Control Module (ARTCM) and no faults were found.

History of flight

On January 12, 2003, about 2115 Hawaiian standard time, Hawaiian Airlines Flight 197, a Boeing 717-200, N482HA, rolled unexpectedly to the left during the climb to cruise after departure from Kahului Airport (OGG), Maui, Hawaii. Hawaiian Airlines, Inc., (HAL) was operating the airplane as a scheduled domestic passenger flight under the provisions of 14 CFR Part 121. The airline transport pilot licensed captain, first officer, 3 flight attendants, and 82 passengers were not injured. The airplane was not damaged. The flight departed Kahalui about 2100 as a nonstop to Honolulu (HNL), Hawaii. Night visual meteorological conditions (VMC) prevailed, and an instrument flight rules (IFR) flight plan had been filed.

HAL submitted a written report. The flight departed runway 02 in visual conditions; winds were light at 5-7 knots. Takeoff, departure, and handoff to Departure Control were normal. The captain was the pilot flying, and he engaged the autopilot at 3,000 feet mean sea level (msl). Passing 8,900 feet msl, he said that the airplane experienced an uncommanded rapid roll of 35 degrees to the left. He countered with approximately 50-60 degrees of right aileron input. The autopilot had been engaged, but disengaged automatically during pilot control input. The first officer (FO) asked the captain if he wanted some aileron trim. The captain responded that he desired only a small amount. His thinking was that he did not want to mask the problem. The captain did not feel any vibration, binding, or unusual "control feel" other than the effort required to hold wings level.

The captain indicated that his fuel load was balanced wing to wing. He did not feel any rudder deflection or imbalance. He insisted that throughout the emergency until final landing he did not observe a Master Caution Light or any alert lights on the Flight Management System (FMS). After directing the FO to call up the Configuration synoptic page on the systems display and get the Quick Reference Handbook opened to the appropriate sections, the captain remembered seeing the right aileron and right elevator deflected upward with "white" (not "green") coloration on the synoptic page. He remembered thinking that the aileron deflection would be consistent with his control input to lower the right wing against a left rolling tendency.

The captain directed the FO to squawk 7700 (emergency) and notify approach control of his emergency and intent to return for landing. The captain related that he made a gradual right turn, keeping the bank angle less than 10 degrees, as he held partial control deflection of 45 degrees or so. He had to make several left turns to line up on final for runway 20. He indicated that he was not comfortable with left turns because he had a feeling of "cross controls" to keep in balanced flight and did not want to aggravate the situation.

On final approach, slat/flap extension and lowering of the landing gear was uneventful to 25 degrees flaps. The captain initially briefed the FO that he would make a "flaps 25" landing. However, in view of a 5-knot tailwind component, he directed the FO to extend the flaps in small increments to 40 degrees. He also directed that if any adverse control input resulted, to immediately return the flaps to the next highest (previous) setting. He encountered no adverse reaction, and flew the airplane to a landing with approximately 45 degrees yoke deflection required to maintain a level wing attitude.

Personnel information

Captain

A review of Federal Aviation Administration (FAA) airman records revealed that the captain held an airline transport pilot certificate with a rating for airplane multiengine land. He held a commercial pilot certificate with ratings for single engine land, helicopter, and instrument helicopter. He held type ratings for the DC-9, with a limitation of circling approach in VMC only, and the DHC-7. He held a first-class medical certificate issued on January 21, 2003. It had the limitation that the pilot must wear corrective lenses. The operator reported that the pilot logged 52 hours in the last 90 days, and 13 hours in the last 30 days.

First Officer

The operator reported that the FO logged 85 hours in the last 90 days.

Aircraft information

The airplane was a Boeing 717-200, serial number 55127.

Aileron Trim System

The aileron trim system operates the aileron trim tab on the trailing edge of each aileron. The components of the system are the Aileron and Rudder Trim Control Module (ARTCM), the Aileron Trim Control Unit (ATCU), and the two aileron trim tab actuators. The trim control unit insures that the left and right actuators operate in synchronization.

The two control wheels provide mechanical input that move a control tab on each aileron. The ARTCM is on the aft pedestal. The aileron trim control switch is a 2-pronged switch. The top switch "enables" or activates the unit. The lower switch is for the direction that the pilot wants the aileron trim to move. The switches provide electrical input to the ATCU. The pilot releases the switch, and the trim remains at the last position.

For failure detection, the trim control unit has an interface with the Spoiler Electronic Control Unit (SECU). The SECU sends failure data to the Centralized Fault Display Interface Unit (CFDIU) and to the Versatile Integrated Avionics (VIA) units. Failure data also goes directly from the trim control to the VIA unit, and causes an alert on the systems display, status page.

The aileron trim indication is at the top left side of the CONFIGURATION page with input from the ATCU. The AIL (aileron) pointer indicates the position of the aileron trim tab actuators, and is always white. The pointer moves from center to LWD (left wing down) or RWD (right wing down). The same indication is on the secondary engine page. On the STATUS page, the level 1 alert AIL TRIM FAIL shows under the MAINT (maintenance) heading. There are no audio tones or alerts associated with the aileron when it is in an out of trim position prior to takeoff. There is no master caution associated with the aileron trim. The airplane can be dispatched with an aileron trim failure according to the HAL Minimum Equipment List (MEL).

Tests and research

Initial Hawaiian Airlines Examination

Hawaiian Airlines maintenance personnel conducted an examination under the supervision of the FAA. They completed a thorough visual examination of the airplane and completed flight control checks of the ailerons, flaps, slats, spoilers, elevators, and all trim tabs. They detected no discrepancies. They checked the airplane for electronic fault indications. The read out noted a fault in the no. 1 Flight Control Computer (FCC). The fault indicated an inappropriate aileron servo command response; this was not a hard fault. HAL pointed out that the Fault Isolation Manual (FIM) indicated that this message showed when the Aileron Servo position did not agree with the FCC command. The National Transportation Safety Board investigator-in-charge (IIC) allowed HAL to download the digital flight data recorder (DFDR) to perform initial troubleshooting.

HAL's analysis of the DFDR data indicated that the aileron trim value was 90 percent of full aileron trim authority prior to pushback, engine start, taxi, and takeoff. Their analysis team reviewed data from the previous inbound flight, which had the same flight crew. It appeared that the trim changed from 10 to 90 percent authority about 3 minutes after the previous flight landed at 2003. The trim again shifted following the landing and taxi back of the event flight from 85 percent to 10 percent at 2126.

The captain said that he felt that the airplane was not tracking properly after takeoff. HAL's debrief of the flight crew indicated that they did not see or recognize the excessive aileron deflection on the cockpit screens bef