Overview
On October 27th, 2024, a South African Airways Airbus A330-300, registration ZS-SXJ, performing flight SA-314 from Cape Town to Johannesburg (South Africa), encountered significant pitch oscillations during cruise at FL410, resulting in temporary instability.
• Aircraft Type: Airbus A330-300
• Passengers and Crew: Not specified
• Injuries: None reported
• Damage: Food and beverage carts displaced, minor cabin disruption
Sequence of Events
1. Enroute at FL410
• The flight was cruising about 240nm northeast of Cape Town at FL410.
• The autopilot (AP) initiated pitch oscillations, causing the aircraft to alternate between pitch-up and pitch-down movements.
2. Overspeed Alert
• The crew observed a speed trend vector increase of 40 knots, nearing the overspeed protection (barber pole) range.
• The autopilot was disengaged by the pilot flying (PF) to manually control the aircraft and mitigate the acceleration.
3. Altitude Adjustments
• The aircraft was gently pitched down to reduce the acceleration.
• The crew requested a descent from Air Traffic Control to FL390, increasing the margin between the overspeed and low-speed protection ranges.
4. Cabin Effects
• During the incident, breakfast service was underway.
• Items from passenger trays and trolleys were displaced due to the oscillations, scattering food and beverages across the economy cabin.
5. Landing at Johannesburg
• The flight continued to Johannesburg (O.R. Tambo International Airport) and landed safely without further issues.
Key Findings
1. Operational Factors
• The autopilot disconnect was initiated promptly by the pilot flying, preventing potential overspeed.
• The decision to descend to FL390 effectively restored stability and avoided further complications.
2. Environmental Conditions
• No significant turbulence was reported in the area according to synoptic charts and weather predictions.
3. Aircraft Performance
• An A330-300 operating at FL410 at such an early stage in the flight and on a relatively short route is unusual. This operational factor will be reviewed as part of the investigation.
4. Cabin Disruption
• Cabin crew and passengers experienced minor disruptions due to dislodged food trays and trolleys but no injuries were reported.
Investigation
South Africa’s Civil Aviation Authority (CAA) is investigating the incident. Areas of focus include:
1. Autopilot Systems
• Examination of the autopilot logic and sensors to identify potential anomalies leading to the pitch oscillations.
2. Flight Planning
• Review of operational decisions, including the cruising altitude of FL410 for a relatively short sector.
3. Pilot Actions
• Evaluation of crew response to the event, including the decision to disconnect autopilot and request descent.
4. Cabin Safety
• Analysis of cabin impacts and safety procedures to mitigate risks during such incidents.
Safety Recommendations
1. Operational Planning
• Review flight profiles for A330-300 operations to ensure appropriate cruising altitudes based on aircraft weight and flight distance.
2. Autopilot Systems Check
• Conduct thorough inspections and software updates for autopilot systems to prevent recurrence of pitch oscillations.
3. Cabin Procedures
• Emphasize securing loose items during flight to minimize risks of disruption in unexpected turbulence or oscillations.
Disclaimer
This report is based on available information as of January 8th, 2025. For photo takedown requests, contact takedown@cockpitking.com. Further updates will follow
