An Air India Airbus A320 encountered a critical systems failure in August when the aircraft suddenly lost hydraulic pressure across all three independent systems, rendering key flight controls temporarily unresponsive and causing the plane to descend about 90 metres before stabilising. The incident, which occurred aboard flight AI2379 en route from Phuket to Delhi on August 4, left 24 people injured despite the crew's successful management of the emergency and the aircraft's safe landing in the Indian capital. A preliminary analysis conducted by Airbus, which has been reviewed by Reuters, provides the first detailed technical account of what happened during those critical seconds when the pilots lost the ability to control the aircraft's pitch and roll.
The engineering assessment from Airbus reveals that the aircraft's three hydraulic systems, which are designed to work independently to provide redundancy, failed in rapid succession rather than experiencing a single catastrophic event. During the approximately four-second window when all hydraulic pressure was lost, the pilots became unable to operate the elevators and ailerons—the movable control surfaces on the tail and wings that determine whether an aircraft climbs or descends and whether it banks to either side. This loss of control authority during flight represents one of the most serious scenarios that can occur in commercial aviation, as pilots depend entirely on these hydraulic systems to manoeuvre the aircraft. The aircraft's nose pitched upward during this period, a natural aerodynamic response when control inputs are unavailable.
The first officer's response to the emergency was immediate and textbook-correct: applying maximum nose-down control input to try to prevent the aircraft from climbing further and stalling. However, because the hydraulic systems had failed, these control inputs had no effect on the flight surfaces. Remarkably, within seconds the hydraulic pressure returned across all three systems, restoring control authority to the pilots and allowing them to recover the aircraft. This rapid restoration suggests the issue may have been related to sensor failure or an electrical fault rather than a fundamental structural or mechanical breach in the hydraulic systems themselves, though Airbus has not yet determined the root cause.
The forces experienced by the aircraft during the sudden altitude loss exceeded the design specifications that Airbus establishes for the A320 platform, raising concerns about potential structural damage. Consequently, Airbus has directed Air India to conduct detailed inspections of the airframe to identify any cracks, deformations, or other damage that may have resulted from the abrupt movement. This represents a significant additional safety precaution, as structural damage that goes undetected could compromise the aircraft's integrity during future operations. The inspection requirements underscore how serious the incident was and the level of concern within the manufacturer's engineering team about what actually occurred.
To determine the root cause, Airbus has requested that Air India perform comprehensive testing of the hydraulic systems and conduct detailed examinations of the pressure sensors and switches that monitor hydraulic fluid levels and pressure. These sensors are critical because they alert the flight crew to system status and trigger automatic procedures when pressures drop below safe limits. The manufacturer has also asked that certain sensors be removed and sent for laboratory inspection to determine whether they malfunctioned, and it has suggested that additional checks of the aircraft's electrical wiring may be necessary. This multi-layered investigative approach reflects the complexity of hydraulic system failures, which can originate from mechanical issues, electrical faults, sensor problems, or combinations thereof.
Air India has been asked to provide detailed maintenance records for the aircraft's hydraulic systems from the month preceding the incident, a critical piece of evidence that could reveal whether recent maintenance work inadvertently introduced the problem or whether the aircraft had been operating with an undetected defect. The airline has also been asked to supply more comprehensive accounts from both pilots regarding their actions, observations, and the sequence of events as they experienced them. These pilot statements can often reveal early warning signs or unusual aircraft behaviour that may have preceded the main incident and help investigators understand whether the crew had any indication that something was wrong before the hydraulic pressure loss occurred.
The investigation has been formally classified as a serious incident by Indian authorities, meaning it falls into a category of events that could have resulted in an accident if circumstances had been different. The Aircraft Accident Investigation Bureau of India is leading the investigation with technical assistance from Airbus and France's Bureau of Enquiry and Analysis for Civil Aviation Safety, reflecting the international nature of aviation safety investigations and the involvement of multiple jurisdictions. This multi-agency approach ensures that expertise from multiple sources is brought to bear on understanding what went wrong and how similar incidents can be prevented in the future.
The incident has been complicated by separate revelations that the aircraft's captain tested positive for marijuana in a confirmatory drug test, though no connection has been established between the pilot's drug use and the hydraulic failure. Nonetheless, the positive test result triggered a significant policy response from Air India, which launched mandatory substance testing for all pilots beginning August 13. While this policy change represents a step toward enhanced safety culture, it also reveals potential vulnerabilities in the airline's pre-flight screening procedures and raises questions about how such a situation was permitted to develop in the first place. The airline's initial public statement characterised the incident as turbulence-related, but this description was subsequently removed from official communications, replaced instead with a more accurate characterisation of it as a sudden loss of altitude.
For Air India, the August incident arrives at a particularly sensitive moment in the carrier's operational history. The airline is preparing for a leadership transition as Tewolde Gebremariam, the former chief executive of Ethiopian Airlines, assumes command of the Tata Group-owned carrier. Air India has been struggling with mounting financial losses and faces intensified scrutiny from both safety regulators and the flying public following the tragic June 2025 crash of a Boeing 787 near Ahmedabad, which claimed 260 lives and represented India's worst aviation disaster in recent memory. The new chief executive will inherit an organisation dealing with significant reputational damage and operational challenges.
The timing of the A320 incident underscores the pressure facing Air India as it attempts to restore public confidence and demonstrate its commitment to safety standards. A series of incidents within a short timeframe can erode passenger confidence and invite regulatory intervention, even when the incidents themselves may not be directly related. For the broader aviation industry in South Asia, the incident highlights the critical importance of robust maintenance protocols, redundant safety systems, and thorough investigation procedures. The involvement of Singapore Airlines, which holds approximately 25 percent ownership in Air India, adds another dimension to the incident's significance, as the Singaporean carrier has a vested interest in Air India's safety performance and operational recovery.
The investigation into the August 4 incident continues, with the focus now on determining whether the hydraulic failure was caused by a manufacturing defect, improper maintenance, sensor malfunction, or some combination of factors. Understanding the root cause is essential not only for Air India and the specific aircraft involved but also for the broader A320 fleet, as any systemic issue could potentially affect hundreds of other aircraft in service worldwide. The Airbus A320 has one of the safest operational records in commercial aviation, and maintaining that record depends on thorough investigation of incidents and swift implementation of any corrective actions that may be required. The coming weeks and months will be critical as investigators piece together the technical evidence and work toward a complete understanding of what caused this rare and dangerous loss of flight controls at altitude.
