Airbus A300B4-605R – N90070

Incident Overview

Date: Monday 12 May 1997

Aircraft Type: Airbus A300B4-605R ?

Owner/operator: American Airlines

Registration Number: N90070

Location: near West Palm Beach, FL – ÿ United States of America

Phase of Flight: Approach

Status: Minor, repaired

Casualties: Fatalities: 0 / Occupants: 163

Component Affected: Tail finTail fin

Investigating Agency: NTSBNTSB

Category: Accident

On June 19, 2002, an aviation incident occurred involving a flight from Miami to Miami, where an aircraft experienced a significant loss of control during a descent and subsequent maneuvers. The flight crew initiated a controlled descent to 16,000 feet, but experienced a rapid and uncontrolled loss of altitude and stability. The autopilot engaged, but the power levers moved to the manual limit, leading to a rapid airspeed decrease. The aircraft then stabilized at 178 knots, followed by a series of maneuvers including a right turn, increased power, and a bank angle increase. The autopilot disconnected, and the aircraft experienced a significant roll, resulting in a loss of control and a period of oscillations. The flight crew’s actions, particularly the failure to maintain sufficient airspeed during leveloff, contributed to the incident. An ultrasound inspection revealed two crescent-shaped cracks in the tail fin, indicating a structural failure. Following Airbus’ recommendations, American inspectors examined the tail fin, finding no damage visually, and the aircraft continued its flight until a horizontal stabilizer ultrasound inspection was performed in March 2002. The inspection confirmed the presence of cracks, leading to the fin replacement.On June 19, 2002, an aviation incident occurred involving a flight from Miami to Miami, where an aircraft experienced a significant loss of control during a descent and subsequent maneuvers. The flight crew initiated a controlled descent to 16,000 feet, but experienced a rapid and uncontrolled loss of altitude and stability. The autopilot engaged, but the power levers moved to the manual limit, leading to a rapid airspeed decrease. The aircraft then stabilized at 178 knots, followed by a series of maneuvers including a right turn, increased power, and a bank angle increase. The autopilot disconnected, and the aircraft experienced a significant roll, resulting in a loss of control and a period of oscillations. The flight crew’s actions, particularly the failure to maintain sufficient airspeed during leveloff, contributed to the incident. An ultrasound inspection revealed two crescent-shaped cracks in the tail fin, indicating a structural failure. Following Airbus’ recommendations, American inspectors examined the tail fin, finding no damage visually, and the aircraft continued its flight until a horizontal stabilizer ultrasound inspection was performed in March 2002. The inspection confirmed the presence of cracks, leading to the fin replacement.

Description

The flight was assigned an airspeed of 230 knots and cleared to descend from FL240 to 16,000 feet in preparation for landing at Miami. The FDR indicated that while the autopilot was engaged in the descent, the power levers moved from the mechanical autothrottle limit of 44 degrees to the manual limit of 37 degrees. As the aircraft leveled at 16,000 feet the airspeed decreased. The F/O began a right turn to enter a holding pattern and added some power, which stabilized the airspeed at 178 knots. However, the right bank and the resultant angle of attack (AOA) continued to increase, despite left aileron input by the autopilot. As the autopilot reached the maximum input of 20 degrees, bank angle increased past 50 degrees, and the AOA increased rapidly from 7 degrees to 12 degrees. At this point the stick shaker activated, the autopilot independently disconnected, the power was increased, and full left rudder was used to arrest the roll. The bank angle reached 56 degrees, and the AOA reached 13.7 degrees at 177 knots. The aircraft then pitched down, and entered a series of pitch, yaw, and roll maneuvers as the flight controls went through a period of oscillations for about 34 seconds. The maneuvers finally dampened and the crew recovered at approximately 13,000 feet. One passenger was seriously injured and one flight attendant received minor injuries during the upset. An analysis showed that the forces during the upset not only had gone above the design limit of the vertical stabilizer, they also apparently had reached the ultimate limit. In June 1997, Airbus requested that American Airlines perform another inspection of the jet to ensure it was not damaged. American inspectors, following Airbus’ instructions, examined the tail fin. But they did not use methods that would have allowed them to see inside the tail fin. They saw no damage from their visual inspection, and the jet continued to fly until an ultrasound inspection of the horizontal stabilizer was done in March 2002. The inspection found two crescent-shaped cracks at one of the points where the tail fin attaches to the fuselage. The fin was replaced. PROBABLE CAUSE:”The flightcrew’s failure to maintain adequate airspeed during leveloff which led to an inadvertent stall, and their subsequent failure to use proper stall recovery techniques. A factor contributing to the accident was the flightcrew’s failure to properly use the autothrottle.”

Primary Cause

Failure to maintain adequate airspeed during leveloff, coupled with inadequate stall recovery techniques and improper use of the autothrottle.Failure to maintain adequate airspeed during leveloff, coupled with inadequate stall recovery techniques and improper use of the autothrottle.

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