FlySafair Flight FA570 Serious Incident: Rapid Depressurization and Return to Johannesburg (ZS-ZWO)

Incident Overview and Flight Details On Saturday, 2 August 2025, FlySafair Flight FA570, a scheduled international air transport operation under Part 121, departed O.R. Tambo International Aerodrome (FAOR) in Gauteng, South Africa, bound for Abeid Amani Karume International Aerodrome (HTZA) in Zanzibar, Tanzania. The aircraft was a Boeing 737-800 with the registration ZS-ZWO. The flight carried 161 passengers and seven crew members, comprising two pilots and five cabin crew. The pilot-in-command held an Airline Transport Pilot Licence (ATPL) and had a total of 8,965.0 flying hours, including 4,486.0 hours on the aircraft type. ## Pre-Flight and Initial Departure During the initial taxi to the runway, the crew reported low pressure in the left bleed air duct. Following advice from the maintenance control centre (MCC), the aircraft returned to the parking bay. Maintenance personnel troubleshot the defect and released the aircraft as serviceable approximately one hour later. The aircraft subsequently took off from Runway 03L at FAOR at 0806Z. ## In-Flight Emergency and Response During the climb, as the aircraft passed through 30,675 feet toward flight level 350, the Bleed Trip Off amber light illuminated on the right pack overhead panel. The crew confirmed the cabin altitude and initiated an emergency descent. During this descent, both visual and aural cabin altitude warnings activated in the cockpit. The cockpit crew donned oxygen masks and followed the Quick Reference Handbook (QRH) checklist for rapid depressurization. Passenger oxygen masks deployed automatically in the cabin. ## Resolution and Outcome The crew descended to 10,000 feet and maintained a holding pattern to burn off fuel before returning to FAOR for a full-stop landing. The incident was classified as a serious incident (Category 3) by the Accident and Incident Investigations Division (AIID) of the South African Civil Aviation Authority (SACAA). No occupants were injured, and the aircraft sustained no damage. The investigation was conducted under Regulation 12.03.1 of the Civil Aviation Regulations (CAR) 2011 to promote aviation safety and reduce risk, without apportioning blame or liability.