Few situations in aviation create more stress and urgency than an aircraft on ground (AOG) event. The moment an aircraft is grounded due to a mechanical issue, parts shortage, or system failure, the clock starts ticking. Lost flight hours, disrupted schedules, emergency repair costs, and crew availability all come into play at once. For corporate flight departments, charter operators, and private owners alike, an AOG event is more than a maintenance problem. It is a logistical and financial disruption that demands fast, competent action.
The good news is that many AOG situations are preventable with the right maintenance strategy. And when they do happen, having a trusted partner on the other end of the phone makes all the difference. This guide covers what causes AOG events, how to reduce your risk, and how Heritage Aviation provides 24/7 AOG support to get aircraft back in the air as quickly as possible.
What Is an AOG Event?
AOG stands for aircraft on ground. It is an industry-standard designation used when an aircraft is unable to fly due to a technical or maintenance issue that requires immediate resolution. The term is used across commercial airlines, business aviation, and general aviation to signal that a situation needs priority attention.
When a part, service, or repair is tagged as AOG, it moves to the top of the priority list for suppliers, logistics providers, and maintenance facilities. Everyone in aviation understands what AOG means, and the entire supply chain is built to respond accordingly. The goal is always the same: resolve the issue safely and get the aircraft back in service as fast as possible.
AOG events generally fall into two categories. A standard AOG involves an aircraft that is grounded but expected to return to service within a few hours to a day once the issue is addressed. A critical AOG involves extended downtime, often because a part needs to be sourced and shipped or because the repair requires heavy maintenance work that cannot be completed on the spot.
Common Causes of AOG Events
AOG events can happen for a wide range of reasons, and understanding the most common causes helps operators prepare for and respond to them more effectively.
Mechanical failure is one of the most frequent triggers. Critical systems like engines, hydraulics, avionics, and landing gear contain thousands of individual components, and even a small fault in a key part can render an aircraft unsafe to operate until repairs are completed. Turbine engines alone are made up of tens of thousands of parts, each of which must be carefully monitored and maintained throughout its service life.
Parts availability is another major cause. An aircraft might be diagnosed quickly, but if the replacement part is not in stock locally, the repair timeline can extend by hours or even days while the component is sourced and shipped. This is especially common with older aircraft types or specialized components that are not widely stocked.
Maintenance delays also contribute to AOG situations. Scheduled maintenance that runs longer than expected, whether due to unexpected findings during an inspection or delays in receiving technical data, can push an aircraft into AOG status if it misses its planned return-to-service window.
Environmental and operational factors round out the list. Severe weather, bird strikes, foreign object damage on the runway, and even software or avionics glitches can ground an aircraft without warning.
The Real Cost of Aircraft Downtime
The financial impact of an AOG event goes well beyond the cost of the repair itself. For charter and Part 135 operators, a grounded aircraft means canceled flights, lost revenue, and potential contractual penalties. For corporate flight departments, it can mean missed meetings, delayed executive travel, and scrambling for commercial alternatives. For private owners, it often means unexpected expenses at the worst possible time.
There are also indirect costs that add up quickly. Hangar fees at an unfamiliar airport, crew hotel and per diem expenses, repositioning costs if a replacement aircraft is needed, and the administrative burden of rescheduling all contribute to the total impact. The longer an aircraft sits on the ground, the more those costs compound.
This is why AOG response time matters so much. A maintenance facility that can diagnose the problem quickly, source parts efficiently, and execute the repair without unnecessary delays can save an operator thousands of dollars in downstream costs. Speed and competence go hand in hand.
How to Prevent AOG Events
While no operator is completely immune to the occasional surprise, most AOG situations stem from one root cause: deferred or inconsistent maintenance. A proactive approach to aircraft care dramatically reduces the likelihood of an unplanned grounding.
Regular inspections and scheduled servicing are the foundation of AOG prevention. Following the manufacturer’s recommended maintenance intervals, staying current on Airworthiness Directives, and addressing Service Bulletins in a timely manner keeps systems operating within their designed parameters and catches developing issues before they become critical failures.
Maintenance tracking is equally important. Using programs like CAMP, CESCOM, or Flight Docs to monitor due items, life-limited components, and time-sensitive inspections ensures that nothing falls through the cracks. Heritage Aviation’s aircraft management team provides daily review and tracking of these items for clients who want that level of oversight without managing it themselves.
Building strong relationships with trusted maintenance providers and parts suppliers is another key factor. When an AOG event does occur, having an established partnership with a facility like Heritage Aviation means you know exactly who to call and can count on a fast, reliable response. Operators who wait until an emergency to find a maintenance provider are at a significant disadvantage.
Detailed record-keeping also plays a role. Clean, well-organized maintenance logs help technicians diagnose problems faster because they have a complete picture of the aircraft’s service history, recent work, and any recurring issues.
Heritage Aviation’s Approach to AOG Response
Heritage Aviation has been providing emergency aircraft repair and AOG support from its FAA-certified Part 145 repair station at Burlington International Airport for over 30 years. The team understands that when an aircraft is on the ground, every hour counts.
Heritage Aviation’s AOG response starts with experienced troubleshooting. The maintenance team brings decades of hands-on experience across a wide range of general aviation and business aircraft types, including Citations, turboprops, and piston-engine aircraft. That depth of knowledge allows them to diagnose issues quickly and develop a repair plan without wasting time.
If an aircraft is grounded away from the Heritage facility, the team can coordinate remote vendor support, source parts through established supplier relationships, and provide logistical guidance to get the repair completed wherever the aircraft is located. Whether the aircraft is on the ramp in South Burlington or at an airport across the country, Heritage Aviation works within the operator’s Part 91 or Part 135 requirements to resolve the situation as quickly and safely as possible.
The AOG hotline is available around the clock. Operators and pilots can reach the Heritage Aviation team at (802) 863-3626, Option 2 for immediate AOG assistance at any time of day or night.
Why Location Matters for AOG Support
Where your maintenance provider is located can have a significant impact on how quickly an AOG event gets resolved. Heritage Aviation’s position at Patrick Leahy Burlington International Airport offers several strategic advantages.
The Pratt & Whitney Canada engine service center is located right next door, which means engine-related AOG issues can often be addressed without the delays of shipping components to a distant facility. For turbine-powered aircraft, that proximity alone can shave days off a repair timeline.
Heritage Aviation’s full-service FBO also means that pilots and passengers arriving for an unplanned maintenance stop have access to ground handling, fueling, a comfortable pilot lounge, courtesy vehicles, and executive conference rooms while they wait. U.S. Customs and Immigration is on site as well, making Heritage a convenient option for international operators who experience an AOG situation while transiting between the U.S. and Canada.
Vermont’s location within easy reach of major Northeast cities and the Canadian border means that many operators are already within a short flight of the Heritage facility. And once you land, there is no sales tax on aircraft parts or labor in the state, which helps offset the unexpected costs that come with any AOG event.
The Role of Avionics in AOG Events
Avionics failures are an increasingly common cause of AOG situations as aircraft systems become more complex and integrated. A malfunctioning GPS, a failed autopilot, a communication radio that will not transmit, or a display screen that goes dark can all ground an aircraft just as effectively as a mechanical failure.
Heritage Aviation’s avionics department is equipped to handle these situations with speed and precision. The team brings over 80 combined years of experience and is an authorized sales, installation, and service facility for most major avionics manufacturers. They carry calibrated digital test equipment for all troubleshooting and repair work, and their bench-level evaluation capabilities allow them to diagnose component-level issues without unnecessary parts swaps.
For IFR-equipped aircraft, Heritage Aviation also provides FAR 91.411 and 91.413 certifications, which are required for operating in controlled airspace. If an avionics issue puts your IFR certification out of compliance, the Heritage team can address the root cause and recertify the system so you can get back on your flight plan.
What to Do When Your Aircraft Goes AOG
If your aircraft is grounded due to a maintenance issue, here is a practical sequence to follow.
First, assess the situation. Identify the symptoms and gather as much information as possible about what happened. Did a warning light come on during preflight? Did a system fail in flight? Was an issue discovered during an inspection? The more detail you can provide to your maintenance team, the faster they can start troubleshooting.
Second, contact your maintenance provider immediately. If you have an established relationship with a Part 145 repair station like Heritage Aviation, call their AOG line and provide the aircraft type, location, symptoms, and any relevant maintenance history. If the aircraft is at your home base, coordinating the repair is straightforward. If you are at an unfamiliar airport, your maintenance provider can help coordinate remote support or guide you to the nearest qualified facility.
Third, document everything. Take photos of any visible damage or anomalies, note the exact circumstances of the failure, and keep a record of all communications with maintenance providers, parts suppliers, and logistics coordinators. This documentation will be valuable for warranty claims, insurance purposes, and your ongoing maintenance records.
Fourth, communicate with your team. If you are managing a flight department or charter operation, notify dispatch, crew scheduling, and any affected passengers as soon as possible. Transparency about the timeline helps everyone adjust and reduces the downstream disruption.
Preventive Maintenance Programs That Reduce AOG Risk
The most effective way to reduce AOG risk over the long term is to enroll in a structured preventive maintenance program. Rather than reacting to problems as they occur, a preventive approach identifies and addresses potential issues during scheduled maintenance events before they have a chance to cause an unplanned grounding.
Heritage Aviation’s aircraft maintenance management services are designed with this philosophy in mind. The team uses industry-leading tracking programs to provide daily review of all due items, Airworthiness Directives, and Service Bulletins across a client’s fleet. Life-limited components are monitored closely so replacements can be planned and parts sourced well in advance of their expiration.
For Cirrus owners specifically, Heritage Aviation’s status as a Cirrus Authorized Service Center means the team is deeply familiar with the SR series maintenance requirements, common failure points, and manufacturer-recommended service intervals. That specialized knowledge translates directly into fewer surprises and more predictable maintenance outcomes.
The bottom line is that the cost of a well-managed preventive maintenance program is almost always less than the cost of a single AOG event when you factor in the repair, the downtime, and the operational disruption.
Employee Ownership and AOG Response Quality
Heritage Aviation is a 100% employee-owned company, and that ownership structure directly impacts the quality of AOG response. When every technician, customer service representative, and line crew member is a shareholder in the business, there is a personal incentive to go above and beyond for every customer, especially during high-pressure situations like an AOG event.
Employee-owned companies consistently outperform their peers in customer service and quality metrics, and Heritage Aviation’s track record reflects that. The company has been recognized as one of the Best Places to Work in Vermont for nine consecutive years, and its 5-star Airnav rating speaks to the level of service that pilots and operators experience firsthand.
That culture of ownership and accountability is exactly what you want behind your aircraft when it is sitting on the ground and you need it back in the air.
Contact Heritage Aviation for 24/7 AOG Support
When your aircraft is on the ground, you need a team that picks up the phone, understands the urgency, and has the experience and resources to get you flying again. Heritage Aviation’s FAA-certified Part 145 repair station in South Burlington, Vermont provides around-the-clock AOG support for general aviation and business aircraft operators across the Northeast and beyond.
Call the Heritage Aviation AOG hotline at (802) 863-3626, Option 2 for immediate assistance.
