What is A Galley? And How Does it Work?

If you are looking to become a flight attendant, you must become accustomed with the concept of airplane galley. For curious travelers on the other hand this is the chance to get an inside look at one of the key pieces of equipment that makes on board service possible. So, let’s dive into what is a galley and how does it work?

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Table of Contents

• The Anatomy of a Galley (Monuments & GAINs)
• The Cart Size Nightmare: Atlas vs. KSSU
• Wet vs. Dry Galleys: It’s All About Plumbing
• The Machinery: Convection, Steam & Espresso
• The Operational Crisis: SpaceFlex & Densification
• The Future: Smart Galleys and The CUBE

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The Anatomy of a Galley

Calling a galley a “kitchen” is misleading. A kitchen implies permanent appliances and fixed layouts. An aircraft galley is a modular logistical hub.

In technical terms, the structure you see bolted to the floor is called a Monument. Think of it as a structural skeleton or a shell. It provides the power, water, and structural integrity, but on its own, it does nothing.

Functionality is added via GAINs (Galley Inserts). These are the modular components – ovens, coffee makers, chillers – that slide into the monument. The brilliance of this system is interchangeability. If a coffee maker breaks on a 737, maintenance doesn’t repair it on board. They pop it out, slide in a new one, and the plane pushes back on time.

But here is where the industry gets messy: Standardization.

The Cart Size Nightmare: Atlas vs. KSSU

You’d imagine that all catering carts (standard units) across all airlines have the same dimensions, right? Wrong.

Airlines find a way to weave complexity into every aspect of their operations, even catering trolleys.

The aviation industry has split into two incompatible standards for the metal catering carts:

• Atlas: The global standard. In the order of 80% of airlines use this cart size in their operations. The beauty of using this standard is that catering trolleys are 100% compatible across airlines and aircraft. You can get a cart from a Lufthansa A350 and slide it onto the rack on a Qantas 787.
• KSSU: The legacy alternative. The acronym stands for KLM, SAS, Swissair, UTA (the last two are defunct). These containers are a slightly different size.

Why Does This Even Matter?

It sounds like a minor detail until you are a fleet manager.

1. Leasing Nightmares: If an Atlas-standard airline damp-leases a plane configured for KSSU, their own inventory won’t fit. They literally cannot load their standard meal carts into the galley.
2. Mergers & Acquisitions: When airlines merge, mixed fleets are a financial black hole. To standardize the cabin, the airline has to rip out the entire galley monument – a multimillion-dollar retrofit – just to make the carts fit.

Following a merger resulting in a mixed Atlas and KSSU fleet, in order to standardize operations you’d have to completely replace the monument (the galley shell) which costs a fortune.

Wet vs. Dry Galleys: It’s All About Plumbing

Not all galleys are created equal. When roaming the passenger cabin you might have noticed some galleys look substantially less complex than others.

That’s where the Wet vs. Dry galley distinction comes into play.

Wet Galleys

These are the galleys where the real action takes place. A wet galley is connected to the aircraft’s potable water system and the grey water drainage systems.

• Requirements: They require complex plumbing and heavy-duty electrical wiring (usually 3-phase 115V AC 400Hz) to power high-draw GAINs.
• Function: This is where you find water heaters, coffee makers (BevMakers), and steam ovens.
• Constraint: Because they require drainage lines that run through the floor structure, Wet Galleys are difficult and expensive to move during a cabin retrofit.

Dry Galleys

These are little more than storage spaces. You’ll notice crew tend to man them significantly less during flights. They offer storage and cooled spaces.

• No Water: There are no faucets, no drains, and no coffee machines.
• Function: They house chilled trolleys, duty-free storage, and dry goods.
• Flexibility: Since they don’t need plumbing, airlines often place these mid-cabin or move them around more easily during layout changes.

The Machinery: More Than Just Ovens

Inside the monuments, you find the GAINs (Galley Inserts). This is where the technology has evolved rapidly. If you think airline food tastes bad because of the food itself, you are only half right. It’s often the machinery.

1. Convection vs. Steam Ovens (Regeneration)

In the industry, we don’t “cook” food; we regenerate it. Food is prepared in advance and not on the spot on the aircraft, even in premium cabins.

Technology has moved forward significantly over the years making food finally taste better onboard.

• Convection Ovens: The standard workhorse for Economy Class. They use a fan to circulate hot dry air (usually 160°C for 20 minutes).
  • The Problem: At 35,000 feet, humidity is already near 0%. Convection ovens strip the remaining moisture out of the meal. This is why pasta in Economy often has a “crunchy” top layer.
• Steam Ovens: The standard for Business/First. These inject moisture into the heating cycle.
  • The Result: Proteins stay tender, and pasta doesn’t dry out. If you are eating a moist steak in the sky, thank the steam injector, not just the chef.

2. The Chilling Systems

Food safety regulations are strict. Carts must stay below 4°C. There are two ways airlines achieve this:

• Air-Over (Chillers): The galley blows cold air around the carts. It’s loud (that “whooshing” noise you hear in the galley) and inefficient because cold air escapes every time a door is opened.
• Liquid Cooling: A closed-loop system pumps chilled liquid directly into the “cold plate” inside the galley structure. It is silent and highly efficient, but heavier and more expensive to maintain.

3. The Coffee Struggle (BevMakers)

In the past, coffee was made in massive bulk brewers using water from the aircraft tank (which isn’t known for its great taste). Modern Premium cabins now feature Espresso Makers (Nespresso/Iacobucci). These use bottled water and bypass the potable water tank entirely.

The Operational Crisis: SpaceFlex & Densification

If you go out and ask any airline cabin crew which aircraft they hate working on, the most likely answer is the A321neo fitted with a SpaceFlex galley.

This has become a nightmare for cabin crew particularly with the launch of long haul operations on narrow body planes.

Operating medium haul, with catering services, on an A320/A321 is bad enough. Operating long haul with a galley half the size is horrible.

A Crew Nightmare Operating the SpaceFlex Galley

The situation arose with airlines looking to maximize the economics of the A321neo over the comfort of crew working on it.

In order to increase seat capacity of the aircraft, aircraft interior designers and galley designers moved two lavatories into the aft of the plane into the space once dedicated to half of the galley.

That means that galley work surface has been effectively slashed in half and so has working space.

Crew now are working in an extremely small space. Also, in front of the two lavatories are still cart stowage which means crew have to make their way between passengers waiting for the restroom to get to them.

Finally on long haul flights the tiny galley is simply not enough to cope with the number of passengers efficiently. The galley “traffic jams” translate into a slow meal service, which is tangible among passengers in comparison to a wide body aircraft.

What Does The Future of The Galley Hold in Store?

The days of manual counting and heavy trash compactors are numbered. The next generation of galleys is focusing on data and sustainability.

Smart Galleys Leveraging IoT

Manufacturers like Safran and Diehl are introducing “Smart Galleys.” By using RFID tags and IoT technology on catering trolleys and containers, the galley “knows” exactly what is onboard.

In simpler terms this will remove the need to count trays manually. A screen will tell how many chicken, beef and pasta are available.

The Death of the Compactor

For decades, crews used heavy hydraulic trash compactors to crush waste. The new standard is the Safran CUBE.

Instead of crushing, it essentially vacuums waste, allowing for better separation of recyclables. It is lighter, hygienic, and critical for airlines trying to meet “Zero Waste” targets.

Dive Deeper into Cabin Operations

• The Airbus A321XLR: Revolutionizing Long Haul or Crew Nightmare?