Regulations & Safety
Air India Flight AI 315 APU Fire Incident Highlights Aviation Safety
Air India Flight AI 315 experienced an APU fire after landing in Delhi, triggering DGCA investigations amid recent safety concerns.

Air India Flight AI 315 Incident: A Closer Look at Aviation Safety and Operational Integrity
On July 22, 2025, Air India Flight AI 315, operating an Airbus A321 from Hong Kong to Delhi, experienced a fire in its auxiliary power unit (APU) shortly after landing at Indira Gandhi International Airport. The incident occurred during passenger disembarkation, prompting automatic safety systems to activate and extinguish the fire. Fortunately, all 158 passengers and crew members disembarked safely without injury.
This event, while contained, has drawn significant attention due to its timing, just one day after two other safety-related incidents involving Airlines Air India aircraft, and barely a month after the tragic crash of a Boeing 787 in Ahmedabad. With regulatory authorities like the Directorate General of Civil Aviation (DGCA) now investigating, the APU fire has become a focal point for broader discussions on aviation safety standards, airline accountability, and public confidence in India’s national carrier.
In this article, we examine the technical aspects of the APU system, the timeline and response to the incident, Air India’s recent safety record, and the wider implications for aviation safety both in India and globally.
Understanding Auxiliary Power Units (APUs)
What is an APU?
An Auxiliary Power Unit (APU) is a small turbine engine typically located in the tail section of Commercial-Aircraft. It provides electrical power and compressed air to aircraft systems when the main engines are off, especially during boarding, ground operations, or in-flight emergencies. The APU is essential for starting the main engines and maintaining critical systems such as air conditioning and cockpit electronics.
In the case of Airbus A321 aircraft, like the one involved in the Air India incident, the APU is designed with fail-safe mechanisms. These include automatic shutdown features and integrated fire suppression systems that activate in the event of abnormal heat or smoke detection.
Modern APUs are equipped with fire-resistant housing and sensors that monitor temperature, pressure, and fuel flow. These features are intended to minimize the risk of fire spreading and to ensure that any fire-related event is quickly contained.
“APU fires are typically minor. The housing contains built-in extinguishers, and cockpit controls allow manual suppression. This incident reflects robust system design, not systemic failure.” , Captain Mohan Ranganathan, Aviation Safety Expert
How APU Fires Occur
Though rare, APU fires can occur due to fuel leaks, residual fuel combustion, or mechanical failures. In this incident, technical experts suggested that residual fuel in the APU system after engine shutdown could have ignited, triggering the fire detection system. The automatic shutdown mechanism functioned as designed, preventing escalation.
Fire suppression systems in APUs are typically activated by sensors that detect high temperatures or smoke. In Airbus aircraft, the cockpit also allows pilots to manually discharge fire extinguishers into the APU compartment if needed.
This layered safety approach ensured that the incident remained isolated and did not impact passenger safety or airport operations. Nonetheless, it raises questions about maintenance practices and whether the APU had been inspected recently for potential fuel system issues.
Chronology and Immediate Response
Timeline of the Incident
Flight AI 315 landed at Delhi Airport at approximately 12:12 PM IST. As passengers began disembarking, smoke was observed near the aircraft’s tail section, prompting immediate concern. The APU’s built-in safety features automatically shut down the unit within seconds, and the onboard fire suppression system deployed successfully.
Airport fire and rescue teams were alerted and arrived promptly. However, by the time they reached the aircraft, the fire had already been extinguished by the aircraft’s internal systems. No external firefighting was required, and there was no damage to airport infrastructure or disruption to other flights.
Following the incident, the aircraft was grounded for inspection. The DGCA was notified and initiated a formal investigation to assess the cause of the fire and evaluate Air India’s compliance with maintenance protocols.
Operational and Technical Impact
The aircraft, registered as VT-PPJ, sustained damage localized to the APU compartment. While no passengers were harmed, the incident prompted a full technical review of the aircraft’s APU and fuel systems. The aircraft remains grounded pending the outcome of the investigation.
Air India reported the event as a “minor technical issue,” emphasizing that safety systems worked as intended. However, the incident adds to a growing list of safety-related events involving the airline, intensifying public scrutiny and regulatory oversight.
There were no delays or cancellations at Delhi Airport as a result of the incident, underscoring the effectiveness of the emergency response and containment protocols in place.
Air India’s Recent Safety Record
Multiple Incidents in a Short Span
The APU fire marks the third safety-related incident involving Air India within 48 hours. On July 21, 2025, a flight from Kochi to Mumbai veered off the runway during heavy rain, and another flight from Delhi to Kolkata aborted takeoff due to a technical fault. These incidents followed the June 12 crash of a Boeing 787 in Ahmedabad, which resulted in 274 fatalities.
These events have raised concerns about systemic issues within Air India’s operations. The DGCA has issued nine show-cause notices to the airline over the past six months, citing violations related to maintenance, crew scheduling, and safety documentation.
In June 2025, three senior officials were removed from crew scheduling duties after the DGCA found violations of flight duty time limitations, which could contribute to pilot fatigue, a known Safety risk.
Regulatory and Public Reactions
In response to the APU fire and other recent events, the DGCA has mandated inspections of all Airbus A320 and A321 aircraft operated by Indian carriers within 30 days. This measure aims to identify any recurring issues related to APU systems or maintenance practices.
Public confidence in Air India has been shaken, with a reported 17% drop in bookings within 48 hours of the APU incident. Industry analysts suggest that competitors may leverage this moment to highlight their own safety protocols.
The Tata Group, which acquired Air India in 2022, has invested heavily in rebranding and modernizing the airline. However, these incidents threaten to undermine those efforts unless systemic issues are addressed transparently and urgently.
Conclusion
The APU fire on Air India Flight AI 315 was effectively contained due to robust aircraft design and prompt emergency response. While it did not result in injuries or major damage, it occurred within a broader pattern of recent safety incidents that have put Air India under intense scrutiny.
Going forward, the airline must prioritize operational transparency, rigorous maintenance protocols, and compliance with regulatory standards. The DGCA’s ongoing investigation will be crucial in determining whether this was an isolated event or indicative of deeper systemic issues.
FAQ
What is an APU and why is it important?
An Auxiliary Power Unit (APU) provides electrical power and air conditioning when the main engines are off. It is also used to start the main engines and serves as an emergency power source.
Was anyone injured in the Air India APU fire?
No, all 158 passengers and crew members disembarked safely without any injuries.
What actions are being taken after the incident?
The DGCA has launched an investigation and mandated inspections of APU systems on similar aircraft across Indian carriers. The affected aircraft has been grounded for technical evaluation.
Sources: Livemint, NDTV, Economic Times, Hindustan Times, SKYbrary Aviation Safety, Pilot Institute, FlightGlobal
Photo Credit: Aviation A2Z
Regulations & Safety
FAA Opens $40M ATC Manufacturing Facility in Maryland
The FAA opened a $40M Rohde & Schwarz USA plant in Frederick, MD to produce VoIP switches for national ATC modernization by 2028.

On August 25, 2026, the Federal Aviation Administration (FAA) and the U.S. Department of Transportation (USDOT) inaugurated a new $40 million manufacturing facility in Frederick, Maryland, dedicated to producing digital Voice over IP (VoIP) switches for the nation’s air traffic control network.
The 87,000-square-foot plant, operated by Rohde & Schwarz USA, represents a critical node in the FAA’s aggressive timeline to complete a nationwide air traffic control modernization overhaul by the end of 2028. According to an agency press release, the facility will build the CERTIUM Voice Communication System (VCS) to facilitate communication between air traffic controllers, pilots, and other control facilities.
Accelerating Air Traffic Control Modernization
The modernization effort is backed by a $12.5 billion down payment from the Working Families Tax Cut. U.S. Transportation Secretary Sean P. Duffy and FAA Administrator Bryan Bedford attended the opening to highlight the administration’s focus on domestic Manufacturing for critical aviation Infrastructure.
“Under President Trump, we aren’t just modernizing our skies at record speed—we’re putting American workers, American manufacturing, and American innovation first,” Duffy stated. “We’re making sure our air traffic control system is American made.”
Bedford emphasized the strict timeline driving the agency’s current procurement Strategy. He noted that the new facility supports the aggressive schedule to complete the new system by the end of 2028 while strengthening domestic production capabilities and creating high-quality jobs. Bedford described the equipment as a critical part of the landmark modernization effort.
Infrastructure Overhaul and Deployment Milestones
The opening of the Frederick plant follows a year of rapid infrastructure deployment by the FAA. The agency recently completed Wave 1 of its nationwide CERTIUM VCS deployment ahead of schedule. This milestone was marked by the installation of the 140th system at the Rapid City Regional Airport (RAP) control tower in South Dakota.
Beyond voice communication systems, the FAA has executed a massive infrastructure overhaul over the past year. The agency reports that 63 percent of legacy copper wires in air traffic control facilities nationwide have been replaced with high-speed fiber, 5G wireless, or Low Earth Orbit (LEO) capabilities.
Additional upgrades completed over the past year include the conversion of 388 radio sites and the installation of 176 IP voice switches. The FAA also deployed Surface Awareness Initiative technology at 96 towers, transitioned 21 towers to electronic flight strips, installed SMR4 Surface Movement Radars at five Airports, and added nine new Tower Simulation systems for controller Training.
AirPro News analysis
The opening of the Rohde & Schwarz USA facility in Maryland underscores a strategic shift toward localizing the supply chain for critical aviation infrastructure. By anchoring the production of digital VoIP switches domestically, the FAA mitigates supply chain risks that have historically delayed large-scale aerospace and infrastructure projects. We view the $12.5 billion funding injection as a substantial catalyst, though the 2028 completion target remains highly ambitious given the historical complexities of integrating new technologies into the national airspace system without disrupting active operations.
Sources: Federal Aviation Administration
Photo Credit: Federal Aviation Administration
Regulations & Safety
Global Aerospace Issues Hangar Foam Suppression Safety Guidelines
Global Aerospace updates hangar fire suppression guidelines, citing 200+ accidental foam discharges and the shift to PFAS-free alternatives.

Global Aerospace has issued updated safety and risk mitigation guidelines for aviation hangar fire suppression systems, highlighting the severe financial and environmental toll of accidental foam discharges. The aviation insurer published the comprehensive best practices on August 24, 2026, detailing the industry transition toward alternative fire protection technologies.
The guidance arrives alongside the introduction of the 2026 edition of National Fire Protection Association (NFPA) 409. This updated standard governs hangar fire protection and introduces critical changes to align requirements with modern aircraft design and growing environmental concerns regarding chemical suppressants.
The financial and human cost of accidental discharges
Fire suppression standards established in the mid-1970s heavily prioritized foam systems to combat large fuel-spill fires. However, Global Aerospace reports that these systems frequently cause more damage than the fires they are designed to prevent. Over the last two decades, more than 200 unnecessary foam discharges have occurred in aviation facilities.
These accidental activations have resulted in tens of millions of dollars in total damages, with the average per-incident cost reaching hundreds of thousands of dollars. Beyond property damage to aircraft and hangar infrastructure, accidental discharges pose severe life-safety risks to personnel.
The insurer cited a fatal 2014 incident at Eglin Air Force Base as a primary example of these hazards. Following a broken sprinkler pipe, the hangar filled with approximately 17 feet of foam in minutes, resulting in the death of one contractor.
Shifting standards and environmental-impact liabilities
Aviation insurers are increasingly processing claims that extend beyond immediate property damage to include long-term health risks and environmental restoration. This liability shift is largely driven by the presence of perfluoroalkyl substances (PFAS) in older aqueous film-forming foams (AFFF).
To mitigate these chemical risks, the aviation industry is actively transitioning toward fluorine-free foams and alternative fire suppression technologies. Global Aerospace highlighted the growing adoption of ignitable liquid drainage floor assemblies and optical flame detection systems, such as multi-spectrum infrared detectors. These alternatives eliminate hazardous chemicals and significantly reduce the likelihood of false alarms.
While the 2026 edition of NFPA 409 provides the framework for these modern systems, the updated standards must be adopted by local fire marshals before facilities can implement the changes.
Operational risk mitigation strategies
For facilities still operating legacy high-expansion foam (HEF) or AFFF systems, Global Aerospace recommends strict operational protocols to minimize the risk and impact of an accidental discharge. The insurer advises operators to protect all aircraft openings and secure sensitive electronics during maintenance operations.
In the event of a discharge, the guidelines stress the importance of keeping hangar doors closed to contain the foam and prevent environmental contamination outside the facility. Additionally, Global Aerospace recommends conducting all system testing and maintenance during off-hours to limit personnel exposure and operational disruption.
AirPro News analysis
The publication of these guidelines by a major aviation insurer underscores a broader industry reality: insurance providers are often the primary catalyst for operational safety upgrades. While regulatory bodies like the NFPA set the baseline standards, the financial pressure of uninsurable environmental liabilities tied to PFAS contamination is forcing hangar operators to modernize. We expect the transition to optical flame detection and drainage floor assemblies to accelerate rapidly as insurers begin pricing the risk of legacy foam systems out of the market.
Sources: Global Aerospace
Photo Credit: Global Aerospace
Regulations & Safety
NTSB Preliminary Report: Ryanair 737-800 Engine Failure
NTSB confirms fan-blade-out on Ryanair 737-800 shattered cabin window, partially ejecting a passenger during climb from Thessaloniki.

This is a developing story. Information may change as official details are released.
This is original reporting and analysis by AirPro News.
On August 13, 2026, the National Transportation Safety Board (NTSB) issued its preliminary report on a July 10 uncontained engine failure aboard a Ryanair Boeing 737-800, confirming that a fan-blade-out event shattered a cabin window and caused a rapid decompression. The incident resulted in a 61-year-old male passenger being partially pulled through the shattered window before being secured by fellow passengers.
The event occurred during climb out from Thessaloniki International Airport (SKG) in Greece. The flight, operated by Ryanair subsidiary Malta Air, was bound for Memmingen, Germany (FMM). The NTSB is currently investigating potential similarities between this event and a fatal 2018 engine failure, while the agency has also publicly addressed premature speculation regarding the cause by Ryanair leadership.
Flight 1879 rapid decompression
According to the NTSB preliminary report, the Boeing 737-800 was climbing when the right-hand CFM56-7B engine experienced a fan-blade-out event. Debris from the engine struck the fuselage and shattered a window at row 11. The resulting rapid decompression pulled a passenger partially outside the aircraft. The passenger sustained neck and shoulder injuries as well as friction burns, but no fatalities occurred.
Reporting by The Air Current indicates the failure happened at an altitude of approximately 15,000 feet. Passengers described a sudden and violent disruption to the flight. A passenger told AP News that the cabin was quiet before a loud noise resembling a bursting tire occurred, adding that they knew immediately the aircraft had lost pressure due to the sudden loss of altitude.
Initial reports following the July 10 incident suggested the failure occurred in the airspace of the Republic of North Macedonia. However, flight path analysis confirmed the event took place in Greek airspace. The Hellenic Air and Rail Safety Investigation Authority officially delegated the investigation to the NTSB on July 16, 2026.
Maintenance history and preliminary findings
The NTSB preliminary report notes that bird remains were found inside the damaged engine. Flight crews had reported four suspected bird strikes to the aircraft’s number two engine in the 12 months preceding the accident. The report states that bird remains were found in two of those previous cases.
Maintenance records indicate that the fan blades on the failed right engine underwent ultrasonic inspections in November 2025 and May 2026. No damage was found during either inspection. The official cause of the July 10 failure remains under investigation by the NTSB, with participation from the Federal Aviation Administration (FAA), Boeing, and CFM International, a joint venture between GE Aerospace and Safran.
Regulatory protocols and historical precedent
The investigation has generated friction between the NTSB and Ryanair regarding public communications. On August 7, 2026, NTSB Chair Jennifer Homendy issued a letter to Ryanair CEO Michael O’Leary after he told investors the investigation was focused on foreign object damage rather than aircraft age or maintenance. Homendy stated that the NTSB had made no such determination and noted that O’Leary’s comments violated International Civil Aviation Organization (ICAO) Annex 13 protocols governing accident investigations.
The aviation industry is closely monitoring the investigation due to the aircraft and engine types involved. The Air Current reported that the event closely mirrors the April 2018 Southwest Airlines flight 1380 uncontained engine failure, which also involved a Boeing 737-700 and a CFM56-7B engine. That incident resulted in one passenger fatality after a shattered window caused partial ejection, leading the FAA to mandate engine inlet redesigns by July 2028.
The NTSB addressed the historical context directly in its preliminary report:
The investigative team is aware of previous … events with similar engine models that resulted in damage to engine inlets or cowlings and fuselage structures. Determination of any relevant similarities or details between this accident and previous events remains under investigation.
AirPro News analysis
We observe that the public rebuke of a major airline CEO by the NTSB is a rare and significant enforcement of ICAO Annex 13 communication protocols. Operators typically defer entirely to the investigating authority to avoid compromising the integrity of an active probe. The NTSB’s swift correction underscores the agency’s zero-tolerance policy for operator speculation, particularly when an event involves high-profile safety concerns like uncontained engine failures.
The CFM56-7B is one of the most widely used commercial aviation engines in the world. Any investigation involving a fan-blade-out event on this powerplant will naturally draw intense regulatory scrutiny, especially given the precedent set by the 2018 Southwest Airlines accident. While the discovery of bird remains introduces foreign object damage as a variable, we expect investigators will rigorously examine the efficacy of the ultrasonic inspections conducted in November 2025 and May 2026 to understand how the blade failure propagated.
Sources: National Transportation Safety Board
Photo Credit: NTSB
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