Aircraft Ground Power Units: Comparing Major GPU Manufacturers, Specifications, and Selection Criteria

Introduction

Aircraft on the ground still need reliable power. Lights, avionics, air conditioning support systems, cabin preparation, cockpit checks, maintenance activities, and pre-flight operations all require electricity before the aircraft engines are running. This is where the aircraft ground power unit, or GPU, becomes one of the most important pieces of ground support equipment at any airport, MRO facility, military base, or FBO.

A GPU supplies external electrical power to an aircraft while it is parked at the gate, on the apron, inside a hangar, or during maintenance. In many operations, GPUs reduce the need to run the aircraft’s Auxiliary Power Unit, helping operators lower fuel consumption, reduce emissions, decrease noise, and improve turnaround efficiency. For airports with high traffic volume, this can make a major difference in daily operating cost and environmental performance.

However, choosing the right GPU is not as simple as selecting a well-known brand or a common power rating. Different manufacturers design their GPUs for different priorities. Some focus on mobile diesel-powered units for flexible ramp operations. Others specialize in solid-state fixed 400Hz systems for airport gates. Some offer compact 28V DC units for business aviation, while others build rugged GPUs for military aircraft and harsh environments.

This blog post compares the major GPU manufacturers, their product ranges, operational differences, maintenance requirements, and selection criteria. The goal is to help aviation buyers, airport operators, MRO managers, and procurement teams understand what matters before choosing a GPU for their operation.

Table of Contents

Chapter 1: What Is an Aircraft GPU and Why Airports Use It

A clear explanation of how GPUs support aircraft on the ground, reduce APU usage, improve turnaround efficiency, and support safer airport operations.

Chapter 2: Main Types of aircraft ground power unit

A comparison of diesel GPUs, fixed solid-state GPUs, battery-powered GPUs, 400Hz AC units, 28V DC units, and combined AC/DC systems.

Chapter 3: Major GPU Manufacturers and Product Comparison Table

A structured comparison of leading GPU manufacturers, including ITW GSE, TLD, Guinault, Houchin, Tronair, AERO Specialties, HII, and ElectroAir.

Chapter 4: How to Choose the Right GPU for Aircraft and Airport Operations

Key selection factors such as aircraft type, power demand, gate operation, MRO use, mobility, cable length, ambient temperature, and future fleet requirements.

Chapter 5: Operational Differences Between GPU Designs

How diesel, electric, fixed, mobile, and battery-based GPUs differ in real airport and hangar operations.

Chapter 6: Maintenance Requirements and Lifecycle Cost

A practical look at engine servicing, filters, cables, connectors, alternators, load testing, diagnostics, corrosion protection, and total cost of ownership.

Chapter 7: Final Selection Guide and Procurement Checklist

A buyer-focused checklist covering power rating, AC/DC requirements, emission rules, spare parts, warranty, documentation, support, lead time, and long-term reliability.

Chapter 1: What Is an Aircraft GPU and Why Airports Use It

An aircraft ground power unit, commonly known as a GPU, is a ground support equipment system used to supply electrical power to an aircraft while it is parked. Instead of relying on the aircraft’s engines or Auxiliary Power Unit, the aircraft can be connected to an external GPU for safe and stable power during ground operations. This allows the crew, maintenance team, and ground handling staff to operate essential aircraft systems before departure, after arrival, or during maintenance.

Most commercial aircraft require 400Hz AC power, while many smaller aircraft, helicopters, and business jets may also require 28V DC power. This is why GPUs are available in different configurations, including 400Hz AC units, 28V DC units, and combined AC/DC models. A GPU can be mobile, trailer-mounted, towable, fixed at the gate, bridge-mounted, battery-powered, or diesel-driven, depending on the airport layout and aircraft operation.

Airports use GPUs for several important reasons. The first is operational efficiency. When an aircraft arrives at the gate, it still needs electrical power for lighting, avionics, cockpit systems, communication systems, galley equipment, and passenger-related functions. A GPU provides this power immediately and allows the aircraft to remain operational without starting engines or running the APU for long periods.

The second major reason is cost reduction. Running the APU consumes fuel and adds operating hours to aircraft equipment. Over time, this increases maintenance costs and fuel expenses. By using a GPU, airlines and operators can reduce APU running time, lower fuel consumption, and extend the service life of aircraft systems.

The third reason is environmental performance. Airports around the world are under increasing pressure to reduce emissions and noise. GPUs help reduce unnecessary fuel burn while aircraft are parked. This is especially important at busy airports where hundreds of aircraft may be connected to ground power every day. Fixed electric GPUs and solid-state 400Hz systems are particularly useful for airports that want cleaner gate operations.

GPUs also support maintenance safety and reliability. During inspections, troubleshooting, software updates, avionics checks, and system testing, technicians need a stable power source. A high-quality GPU provides clean and consistent power, reducing the risk of voltage fluctuation or equipment damage.

In short, the GPU is not just a power box on the ramp. It is a critical part of aircraft turnaround, airport efficiency, maintenance support, environmental control, and airline cost management.

Chapter 2: Main Types of Aircraft Ground Power Unit

Aviation GPUs are not all the same. The right unit depends on the aircraft type, airport operation, available infrastructure, mobility requirement, environmental policy, and maintenance strategy. In general, GPUs can be divided into several main categories: diesel-powered mobile GPUs, fixed solid-state GPUs, battery or electric GPUs, 28V DC GPUs, 400Hz AC GPUs, and combined AC/DC units.

Diesel-powered mobile GPUs are among the most common solutions for ramp and remote stand operations. These units are usually towable or self-propelled and include an engine, generator, control panel, cables, and aircraft connectors. They are useful when aircraft are parked away from terminal gates or when fixed power infrastructure is not available. Diesel GPUs are flexible and powerful, but they require regular engine maintenance, fuel management, oil changes, filter replacement, and emission control attention.

Fixed solid-state GPUs are commonly installed at airport gates, passenger boarding bridges, hangars, and dedicated aircraft parking positions. These units convert the airport’s electrical supply into the aircraft’s required power, usually 400Hz AC. They are cleaner and quieter than diesel units because they do not use an onboard engine. They are ideal for high-traffic airports, especially where environmental targets and noise restrictions are important. Their main limitation is that they are fixed in position and depend on airport electrical infrastructure.

Battery-powered and electric GPUs are becoming more popular as airports move toward greener ground operations. These units reduce local emissions and noise, making them attractive for indoor hangars, urban airports, and environmentally sensitive locations. However, buyers must consider battery capacity, charging time, duty cycle, climate conditions, and long-term battery replacement cost.

400Hz AC GPUs are used mainly for commercial aircraft and larger business jets. Aircraft electrical systems commonly use 400Hz power because it allows lighter electrical components compared with lower-frequency systems. Common ratings include 60 kVA, 90 kVA, 120 kVA, 140 kVA, and higher capacities for wide-body aircraft or heavy-duty operations.

28V DC GPUs are widely used for smaller aircraft, helicopters, regional aircraft, military platforms, and engine-start support. These units are often smaller and easier to move, but they must still provide stable voltage and sufficient current during peak load conditions.

Combined AC/DC GPUs provide both 400Hz AC and 28V DC output in one unit. They are useful for MRO facilities, military bases, mixed fleets, and operators that service different aircraft types. While they can cost more upfront, they reduce the need for multiple separate units.

Choosing between these GPU types depends on how and where the aircraft will be powered. A busy airport gate may benefit from fixed solid-state GPUs. A remote apron may need diesel mobile units. An MRO hangar may require combined AC/DC capability. A business aviation operator may prefer compact 28V DC power. The correct choice begins with understanding the operation, not only the manufacturer name.

Chapter 3: Major GPU Manufacturers and Product Comparison Table

The aviation GPU market includes several well-known manufacturers, but each company has a different strength. Some are stronger in fixed airport gate systems, some in mobile diesel ramp units, some in 28V DC business aviation GPUs, and others in military or heavy-duty aircraft support. For buyers, the best GPU is not always the most famous model. It is the unit that matches the aircraft fleet, operating environment, maintenance capability, power quality requirement, and long-term support plan.

A key point in GPU selection is to avoid comparing all units only by kVA rating. A 90 kVA GPU from one manufacturer may be designed mainly for mobile ramp use, while another 90 kVA system may be designed for fixed gate operation. Some units offer only 400Hz AC power, while others also include 28.5V DC output. Some are diesel-driven and fully mobile, while others are solid-state converters connected to airport electrical infrastructure. This difference affects noise, emissions, maintenance, fuel cost, mobility, and service life.

The table below summarizes some of the major GPU manufacturers and representative products.

Manufacturer	Example product or range	Main output	Power source / design	Best application	Key advantage	Maintenance and buyer note
ITW GSE / Hobart	ITW GSE 2400 / 1400 series	400Hz AC, 28V DC depending on model	Solid-state, fixed or mobile electric	Airport gates, passenger boarding bridges, hangars	Strong reputation in fixed airport power and low-emission gate operation	Best when airport infrastructure is available. Lower engine maintenance than diesel GPUs, but requires proper electrical installation and service support. ITW also offers 28V DC units with continuous 400A to 600A output and high peak starting capability.
TLD	GPU-409	90 kVA, 400Hz AC	Diesel-driven mobile GPU	Ramp operation, remote stands, mixed airport use	Compact mobile design with full-size 90 kVA performance	Good for flexible ramp use. Requires diesel engine maintenance, fuel handling, filters, oil, and generator inspections. The GPU-409 uses a brushless generator running at optimized RPM for fuel efficiency and sound reduction.
Guinault	GA90, GA180, EGA90, EGA180	90 to 180 kVA, 400Hz AC, optional 28V DC	Diesel or battery-electric models	Civil airports, military bases, high-demand operations	Broad range, including diesel and battery GPUs	Useful when the buyer needs heavy-duty AC power and optional DC output. Guinault lists GA90 at 90 kVA and GA180 at 180 kVA, with optional 28V DC rated at 800A continuous and 2500A peak.
Houchin	690 / C690 series	Commonly 90 kVA, 115/200V, 400Hz, plus 28V DC on some units	Diesel-driven mobile GPU	Commercial ramp, MRO, mixed aircraft servicing	Known for low-noise mobile GPU solutions	Strong option for operators needing conventional diesel AC/DC aircraft servicing. Buyer should check age, engine condition, emissions class, and parts support, especially when buying used units. Used listings commonly show Houchin C690 units around 90 kVA with 400Hz output and 28V DC capability.
Tronair	11-4290-0000	90 kVA 400Hz AC and 28.5V DC	Diesel-driven mobile GPU	MRO facilities, FBOs, aircraft servicing	Practical AC/DC servicing unit with long service interval positioning	Tronair’s 90 kVA unit includes 400Hz AC and 28.5V DC output, with simultaneous AC/DC use. It uses a Doosan Tier 4f electronic engine and states service intervals up to 500 hours.
AERO Specialties / JetGo	JetGo 28V DC series	28V DC, high continuous and peak current depending on model	Diesel-hybrid or electric depending on model	Business aviation, regional aircraft, FBOs, avionics support, engine starts	Compact and mobile 28V DC support	Best for operators that mainly need DC power rather than large 400Hz AC capacity. AERO Specialties describes the JetGo 600Mti-RJ as compact and suitable for avionics support, electrical air conditioning, maintenance, and engine starts, while noting newer JetGo models have replaced earlier versions.
Hydraulics International Inc. / HII	60 kVA and 90 kVA aircraft GPU	400Hz AC and 28V DC	Diesel-generated rugged GPU	Military bases, defense aviation, harsh operating environments	Rugged AC/DC GPU design for demanding use	Strong fit when durability, AC/DC capability, and military-style operation are priorities. HII lists 60 kVA and 90 kVA diesel-generated AC 400Hz and 28V DC GPUs designed for rugged military demand and environment.
ElectroAir	APA-65, APA-165 / APA-165E	28.5V DC, 400Hz AC, high-capacity options depending on model	Diesel, hybrid, or mobile platform	Military, civil aviation, helicopter operations, heavy-duty mobile power	Flexible AC/DC configurations and high-capacity mobile options	Good for buyers needing specialized or high-output configurations. The APA-165 platform is described as offering dual 400Hz AC channels up to 2 × 180 kVA with flexible 28.5V DC and 24/48V engine-start options.

From a procurement point of view, this comparison shows why the buyer should begin with the aircraft requirement rather than the manufacturer name. A commercial airport gate with fixed infrastructure may prefer a solid-state electric GPU. A remote apron may need a diesel mobile 90 kVA unit. A business aviation facility may need compact 28V DC power. A military customer may focus more on ruggedness, AC/DC flexibility, transportability, and environmental resistance.

Another important difference is support philosophy. Some manufacturers are stronger in airport infrastructure projects, while others are stronger in workshop, FBO, military, or remote-field operations. The right choice should consider not only the first purchase price, but also training, spare parts, documentation, warranty, local representation, emission compliance, and long-term maintenance cost.

Chapter 4: How to Choose the Right GPU for Aircraft and Airport Operations

Choosing the right aircraft GPU starts with understanding the real operation, not only the aircraft model or the GPU brand. The same airport may need different GPU solutions for passenger gates, remote stands, cargo aprons, MRO hangars, military areas, and business aviation terminals. A unit that works perfectly at a fixed gate may not be practical for a remote parking position. A compact 28V DC GPU may be ideal for a business jet, but completely unsuitable for a narrow-body commercial aircraft requiring 400Hz AC power.

The first selection factor is the aircraft power requirement. Many commercial aircraft require 115/200V, 400Hz AC power, commonly supplied by 60 kVA, 90 kVA, 120 kVA, 140 kVA, or higher-rated GPUs. Smaller aircraft, helicopters, and some military platforms may require 28V DC power for avionics, battery support, maintenance checks, or engine start. MRO facilities and military bases often prefer combined AC/DC GPUs because they service different aircraft types and cannot rely on one narrow specification.

The second factor is where the GPU will be used. At passenger gates, fixed solid-state GPUs are often preferred because they are cleaner, quieter, and connected to airport electrical infrastructure. They reduce diesel usage, noise, and emissions around the terminal. For remote stands, cargo aprons, temporary aircraft parking, or bases with limited infrastructure, diesel mobile GPUs remain highly useful because they can be moved wherever power is needed.

The third factor is mobility and frequency of use. A GPU used many times per day at the same gate should be easy to access, durable, and simple for ground handlers to operate. A GPU used in an MRO hangar must support longer maintenance cycles, stable output, and technician safety. A GPU used in military or remote operations may need stronger environmental protection, better towing capability, rugged structure, and reliable performance under dust, heat, humidity, or uneven ground conditions.

The fourth factor is environmental and regulatory pressure. Airports are increasingly focused on reducing emissions and noise. This makes electric, battery, and solid-state GPUs more attractive, especially in terminal areas. However, buyers must still evaluate charging infrastructure, power availability, operating duty cycle, and long-term battery replacement cost.

Finally, procurement teams should consider support and lifecycle cost. A lower purchase price can become expensive if spare parts are difficult to obtain, local service is weak, or maintenance intervals are short. Before selecting a GPU, buyers should review documentation, warranty, training, spare parts availability, output quality, cable management, connector type, and after-sales support.

In short, the best GPU is not simply the largest or most famous one. It is the unit that matches the aircraft, location, operating pattern, environmental target, and maintenance capability of the airport or MRO facility.

Chapter 5: Operational Differences Between GPU Designs

Different GPU designs create very different experiences for ground handling teams, maintenance technicians, airport operators, and aircraft crews. The main operational differences come from the power source, mobility, noise level, emission profile, response time, ease of use, and maintenance workload.

A diesel mobile GPU gives the operator maximum flexibility. It can be towed to different aircraft stands, used in remote apron areas, and deployed where fixed electrical infrastructure is not available. This makes it valuable for cargo operations, military bases, temporary aircraft parking, and airports with mixed stand configurations. However, diesel GPUs produce noise and exhaust emissions, require fuel, and need regular engine servicing. Their daily operation also depends on proper start-up checks, fuel level monitoring, cable inspection, and safe positioning around the aircraft.

A fixed solid-state GPU works differently. It is normally installed at a passenger boarding bridge, gate, or hangar position and connected to the airport’s electrical supply. It does not need a diesel engine, so it is quieter and cleaner in daily operation. Ground handlers can connect aircraft power quickly and consistently. This is why many modern airports prefer fixed 400Hz systems at high-traffic gates. The limitation is that the unit cannot be moved to another stand. If aircraft parking positions change frequently, fixed GPUs must be supported by mobile units.

A battery-powered or electric mobile GPU is a middle solution between diesel mobility and low-emission operation. It can move around the ramp while reducing local emissions and noise. This is attractive for airports with sustainability targets and for hangars where exhaust fumes are a concern. The challenge is energy management. Operators must monitor charging, duty cycle, battery health, and peak load. In hot climates, battery performance and thermal management are also important considerations.

A 28V DC GPU has a different operational role compared with a high-capacity 400Hz AC unit. It is often used for smaller aircraft, helicopters, avionics support, maintenance work, or engine starting. It may be easier to move and simpler to operate, but it is not designed to replace a large AC GPU for commercial aircraft ground power.

A combined AC/DC GPU gives more flexibility, especially in MRO and military environments. One unit can support different aircraft needs, reducing the requirement for multiple separate machines. However, these units may be more expensive and require operators to understand both output systems correctly.

Operational choice also depends on climate and ramp conditions. In dusty, hot, humid, or coastal environments, corrosion protection, filtration, cooling capacity, cable quality, and enclosure design become very important. A GPU that performs well in a mild climate may require additional care in the Middle East, where heat, sand, and high operational intensity can affect equipment life.

Chapter 6: Maintenance Requirements and Lifecycle Cost

A GPU should never be evaluated only by its purchase price. The real cost appears over years of operation through fuel use, service intervals, spare parts, downtime, cable replacement, connector wear, battery replacement, software support, and technician labor. For airports and MRO facilities, reliability is as important as technical specification because a failed GPU can delay aircraft turnaround or interrupt maintenance work.

For diesel GPUs, maintenance is similar to other engine-driven ground support equipment. The engine requires oil changes, fuel filter replacement, air filter inspection, coolant checks, belt inspection, battery checks, and regular servicing according to operating hours. The generator and alternator section also need inspection to ensure stable frequency, voltage, and output quality. In dusty or hot regions, air filters and cooling systems may need more frequent attention. Poor maintenance can lead to unstable power, higher fuel consumption, difficult starting, overheating, or unexpected failure on the ramp.

For fixed solid-state GPUs, maintenance is usually less focused on engines and more focused on electrical components, cooling fans, internal electronics, input power quality, software diagnostics, cables, contactors, connectors, and output stability. These units may have lower routine mechanical maintenance than diesel models, but they still require qualified electrical inspection and proper installation. If the airport electrical infrastructure is weak or poorly protected, even a high-quality GPU may experience reliability issues.

For battery or electric GPUs, maintenance includes battery health monitoring, charging system inspection, thermal management, software updates, cable inspection, and checking the condition of power electronics. The buyer must also consider the long-term cost of battery replacement. Battery-powered GPUs may reduce fuel and engine servicing cost, but the total lifecycle cost depends heavily on usage pattern, charging discipline, climate, and battery technology.

Cables and connectors are often underestimated. In daily ramp operation, aircraft power cables are dragged, bent, exposed to heat, hit by vehicles, and connected repeatedly. Damaged cables can cause voltage drop, safety risks, and unreliable power delivery. Regular inspection of connectors, insulation, cable reels, plugs, and strain relief points is essential.

Preventive maintenance should also include load testing, calibration checks, output verification, safety interlock testing, emergency stop inspection, corrosion control, tire and towbar inspection for mobile units, and operator training. Many failures happen not because the GPU is poorly designed, but because the equipment is misused, overloaded, poorly positioned, or operated without proper daily checks.

A good procurement decision should therefore include maintenance capability. Buyers should ask about spare parts availability, local service support, documentation, training, warranty, diagnostic tools, and recommended service intervals. The lowest-price GPU is not always the lowest-cost GPU over its lifetime.

Chapter 7: Final Selection Guide and Procurement Checklist

The final decision for an aircraft GPU should combine technical, operational, financial, and support-related factors. A good GPU selection process begins with a simple question: what aircraft will this unit serve, and under what operating conditions? From there, the buyer can define the correct power rating, AC/DC requirement, mobility level, environmental standard, and maintenance plan.

The first item in the checklist is aircraft compatibility. Confirm whether the aircraft requires 400Hz AC, 28V DC, or both. Then confirm the required kVA rating, voltage, frequency, connector type, cable length, and peak load. Do not assume that all aircraft in the same fleet category have identical ground power needs. Maintenance activities, avionics testing, cabin preparation, and engine start support may create different load demands.

The second item is operation location. For passenger gates, fixed solid-state GPUs may be the best choice because they support quieter and cleaner terminal operations. For remote stands, cargo aprons, military areas, and temporary operations, mobile diesel or electric GPUs may be more practical. For MRO facilities, combined AC/DC capability is often useful because different aircraft types are serviced in the same location.

The third item is environmental policy. Airports with strict emission and noise targets may prefer electric, battery, or fixed power systems. However, this decision must be matched with available infrastructure. A battery GPU without proper charging capacity can become a bottleneck. A fixed GPU without reliable input power can create operational delays.

The fourth item is maintenance and support. Before purchasing, the buyer should check spare parts availability, training, warranty, documentation, service intervals, and local representation. This is especially important in regions where equipment is exposed to heat, dust, humidity, and intensive daily use. Strong after-sales support can be more valuable than a small saving in purchase price.

The fifth item is total cost of ownership. This includes fuel, electricity, battery replacement, engine servicing, filters, tires, cables, connectors, downtime, technician labor, and future upgrades. A more expensive unit may be cheaper over time if it reduces fuel use, downtime, or maintenance frequency.

Finally, buyers should consider future fleet development. Airports and MROs are long-term operations. A GPU purchased today may need to support new aircraft types, higher environmental standards, or different operational layouts in the coming years.

A practical procurement checklist should include:

Selection point	Question to ask
Aircraft requirement	Does the aircraft need 400Hz AC, 28V DC, or both?
Power rating	Is 60, 90, 120, 140 kVA, or higher required?
Mobility	Will the unit be fixed, towable, self-propelled, or portable?
Application	Gate, remote stand, hangar, military base, cargo apron, or FBO?
Environment	Is low noise or low emission operation required?
Climate	Can the GPU operate reliably in heat, dust, humidity, or coastal conditions?
Maintenance	Are spare parts, service, training, and diagnostics available?
Lifecycle cost	What is the real cost over five to ten years?
Documentation	Are manuals, certificates, test reports, and warranty documents included?
Future use	Will the unit support future aircraft and airport expansion?

In the end, the right GPU is the one that provides stable aircraft power, fits the operating environment, supports the maintenance team, reduces unnecessary APU use, and delivers dependable service over many years. For airports, airlines, MRO facilities, and defense operators, a well-selected GPU is not only a ground support purchase. It is an investment in safer, cleaner, and more efficient aircraft operations.