Education

February 4, 2015

Flying in Cargo Class: The Anatomy of an Air Freighter

Passenger and cargo aircraft look very similar from a distance. With a few exceptions, the airplanes used as freighters are the same models frequent fliers are familiar with. As an airliner flies overhead, often the only way to tell it’s not hauling human cargo is the logo of a logistics company. Inside a freighter, it’s a whole other animal.

A FedEx Boeing 777 freighter (Photo credit: Flickr)

A FedEx Boeing 777 freighter. Cargo can be loaded onto both the main and lower decks. (Photo credit: Flickr)

A British Airways Boeing 777, equipped to carry passengers. (Photo credit: Flickr)

A British Airways Boeing 777, equipped to carry passengers on the main deck and cargo under the floor. (Photo credit: Flickr)

Two Types Of Cargo Aircraft – Conversions and Freighter Variants

A few years ago, cargo fleets were comprised primarily of old passenger aircraft. Retired people-haulers go through a conversion process to start a new life as a freighter. Converting an aircraft to a freighter is about a third of the cost of buying a new one, so there is a brisk market for conversions.

When the package express industry exploded a few years ago, manufacturers like Boeing and Airbus began churning out cargo variants directly from the factory in record numbers. These airplanes are born freighters.

It’s easy to tell the difference between a passenger conversion and a factory-built freighter: look for windows.

Passenger conversions have passenger windows. A few still have the old acrylic panes, but on most conversions, the clear windows have been replaced with lightweight aluminum plugs to save on operating costs. Even when they’re painted over, you can see the plugs if you look carefully (they’re easier to see on dirty airplanes).

Factory-built cargo variants are windowless. Installing windows on a fuselage requires extra reinforcement, which means extra weight. Building a freighter without windows lowers manufacturing costs and reduces the aircraft weight by hundreds of pounds. A factory-built freighter will have smooth sides with not a window in sight. 747 freighters usually have windows in the “hump” because that area is used for jumpseats and crew rest facilities.

A Japan Airlines Boeing 747 passenger-to-freighter conversion featuring aluminum window plugs. (Photo credit: Flickr)

A Japan Airlines Boeing 747 passenger-to-freighter conversion featuring aluminum window plugs. (Photo credit: Flickr)

A Cathay Pacific Boeing 747 freighter that began life as a freighter, so no need for window plugs. (Photo credit: Flickr)

A Cathay Pacific Boeing 747 freighter that began life as a freighter, so no need for window plugs. (Photo credit: Flickr)

The Big Door

The most obvious exterior feature of a freighter is the Big Door. Main cargo doors on large aircraft are usually about 11 feet (3.4 m) wide and 7-10 feet tall depending on the diameter of the fuselage. The width of the doors are similar on most aircraft to accommodate standard loading equipment.

The large size and weight of the doors require serious muscle power to raise and lower. Most are powered by hydraulics  – either by the ship’s main system or a dedicated electric hydraulic pump.

For really big missions, many Boeing 747 freighters have a nose cargo door that allows this aircraft to swallow cars, trucks, tanks and even other aircraft.

Most freighters (such as the FedEx MD-11 shown above) include an extra large main cargo door. (Photo credit: Flickr)

Most freighters (such as the FedEx MD-11 shown above) include an extra large main cargo door. (Photo credit: Flickr)

Some freighters (such as this Cathay Pacific 747) have a swing-up nose door for loading extra large items. (Photo credit: Flickr)

Some freighters (such as this Cathay Pacific 747) have a swing-up nose door for loading extra large items. (Photo credit: Flickr)

There is a small fleet of very special 747’s that have a tail that swings open. The Boeing DreamLifter is a highly modified 747 designed to carry fuselage sections for the Boeing 787 DreamLiner. Boeing built only four of these beasts, so it’s an airplane that always attracts the attention of casual onlookers and avgeeks, alike.

Turboprop freighter like the British Aerospace ATP have sliding doors that can been opened by hand.

The Boeing DreamLifter's entire tail section swings left for loading extra large items. (Photo credit: Flickr)

The Boeing DreamLifter’s entire tail section swings left for loading extra large items. (Photo credit: Flickr)

This British Airways ATP freighter conversion includes an added sliding door. (Photo credit: Twitter/@FlattenedVowel)

This ATP freighter conversion includes an added sliding door. (Photo credit: Twitter / @FlattenedVowel)

Crew Entry doors

Conversion freighters typically maintain the original passenger entrance door at the front left of the aircraft. Cargo variants often incorporate a different door with a design and location optimized for the freighter. The Boeing 757-200PF (Package Freighter) variant, and some 757 conversions, have a small hatch instead of a roomy passenger entrance door. The 48” tall hatch is positioned farther forward to create more room for revenue producing cargo. I often joke that I’m climbing into an Apollo Command Module when boarding the 757. Watch your head!

Crew entry door size and position on a 757-200 freighter vs. passenger. (Photo credit: Flickr)

Crew entry door size and position on a 757-200 freighter vs. passenger. (Photo credit: Flickr)

Unlike a passenger 757, the hatch on the freighter does not have an inflatable emergency slide. For emergency egress, there are escape ropes at each side window. The crew hatch has both a rope and a set of inertial escape reels that provide each occupant a safe, controlled descent out of the aircraft (we prefer using air stairs!). Larger cargo aircraft, like the MD-11 and 747, still utilize passenger-style inflatable slides for emergency evacuation.

Main Cargo Deck

Stepping inside a freighter, you can’t help but notice the big, empty interior. Cramped coach seats, business class mini-suites, overhead bins and windows are exchanged for a main deck optimized for cargo. The airplanes pictured below are the same model with the exact same dimensions. Quite a difference.

Boeing 767-300 with 2-3-2 passenger configuration. (Photo by the author)

Boeing 767-300 with 2-3-2 passenger configuration. (Photo by the author)

Boeing 767-300 shown in cargo configuration. (Photo by the author)

Boeing 767-300 shown in cargo configuration. (Photo by the author)

Cargo Deck Floor System

Cargo deck floors are engineered for fast loading and unloading. The floors have heavy duty ball bearing rollers and locks built into them. Specially designed Unit Load Devices (ULDs) are filled with packages and cargo, then lifted onto the aircraft. The ULDs are rolled into position and locked into place with pop-up locks that clamp the ULDs to the floor. The locks assure the cargo doesn’t shift in flight. A fully loaded ULD can weigh over 5000 pounds. That much weight shifting during takeoff could be catastrophic. Loaders are vigilant to assure the ULDs are secured properly.

Some cargo aircraft have an automated cargo-handling system. Power-drive units built into the floor move the ULDs into and out of the airplane. Two operators can load or unload a 747 main deck in minutes with a control panel and joysticks.

Main deck floor rollers and pallet locks. “It's all ball bearings nowadays!” (Photo by the author)

Main deck floor rollers and pallet locks. “It’s all ball bearings nowadays!” (Photo by the author)

Unit Load Device (ULD) ready to be loaded. (Photo by the author)

Unit Load Device (ULD) ready to be loaded. (Photo by the author)

Take a walking tour of a Boeing 767-300 freighter interior

When we arrive at the aircraft for a flight, the main deck is usually a very busy place. On one rare occasion when we ferried an empty jet, I recorded a preflight stroll through the main deck of the aircraft. This also gave me the opportunity to watch the cargo door close from the inside. At the end of the video, notice the latches at the very bottom of the cargo door swing into position to seal and lock the door closed.

Loading, Unloading, And Sorting

UPS produced a really fun time lapse video of its Worldport operation in Louisville, Kentucky. The video does a nice job showing how ULDs filled with packages are unloaded, sorted, and reloaded onto the aircraft.

Crew Areas

The 767-300 freighter flight deck, my home away from home. From the pilot seats forward, it would take an experienced crew member to tell the difference between a freighter and passenger aircraft. Behind the pilot seats, a freighter flight deck is very different from its passenger sibling.

767-300F (freighter) forward flight deck is nearly identical to a 767-300ER (passenger)/ (Photo by the author)

767-300F (freighter) forward flight deck is nearly identical to a 767-300ER (passenger). (Photo by the author)

Everything we need for a long flight is on the flight deck. The 767-300F has room for 4 jumpseaters (or 3 plus an observer). We have a lavatory with a flushing toilet (no sink, but lots of “moist towelettes”), overhead storage, a very small closet and a galley. The galley includes a convection oven, hot water pot, a cooler for juices, water and soda, and food storage areas. All of life’s necessities for a 10 hour flight.

Lavatory aboard the Boeing 767-300 freighter. (Photo by the author)

The Boeing 767-300 freighter’s lavatory. (Photo by the author)

Crew entry door and galley. (Photo by the author)

This narrow area near the crew entry door serves as the galley. (Photo by the author)

Galley oven and hot water pot. (Photo by the author)

Galley oven and hot water pot. (Photo by the author)

767-300 freighter behind the pilot seats. (Photo by the author)

767-300 freighter behind the pilot seats, showing how the rear of the flight deck is laid out. (Photo by the author)

Flight crews on larger cargo aircraft have it pretty good. Space to move around, lavatories, food prep areas, and more. Smaller freighters, like the ATP pictured above, have very limited “crew comfort” amenities. Lavatories are a luxury that must be enjoyed before hopping on the aircraft.

Boeing 747-400 Freighter 

Have you ever wondered what’s in the hump of a 747 freighter behind the flight deck? A bigger airplane means more room to stretch out. It’s not exactly business class but it’s still a very nice way to travel. Jumpseat configurations on the 747 vary depending on the specific model and operator.

Boeing 747-400F - Catering boxes to the rescue! (Photo by the author)

Boeing 747-400F – Catering boxes to the rescue! (Photo by the author)

Jumpseat configuration on a 747-400BCF (Boeing Converted Freighter). (Photo by the author)

Jumpseat configuration on a 747-400BCF (Boeing Converted Freighter). (Photo by the author)

The 747s operated by my company include a full galley, complete with refrigerators and automatic drip coffee. I never turn down 747 coffee! The lavatory is a typical passenger lav that includes the extravagance of hot/cold running water. The real bonus on the big jets are bunks for additional crew members to rest during long flights. 

Converting An Aircraft For A Life Of Cargo

Passenger to cargo conversions are less expensive than buying a new aircraft. Converting a 20-year-old Airbus A300 is about a third of the cost of a brand new aircraft (reference). Depending on the type of operation, buying used and converting can make good financial sense.

How are passenger jets converted to freighters? Is it as easy as ripping out the passenger seats and cutting a big hole for a cargo door? No way! The old passenger jet that enters a conversion facility comes out like a new machine. Nearly every part of the aircraft is disassembled, inspected, cleaned, and repaired. Large portions of the fuselage are removed and completely replaced with specially reinforced sections.

Here’s a time lapse video produced by Boeing that shows this amazing process:

If you’d like to learn more about freighter aircraft, be sure to check out these articles I wrote for NYCAviation and AeroSavvy:

Come Along As We Cross The Pacific – An Inside Look (NYCAviation.com)

Airline Flying: Cargo vs Passengers (AeroSavvy.com)

Photo Credits:

FedEx 777 – Eric Salard

British Airways 777 – Doug

JAL Cargo 747 – Pieter van Marion

Cathay Pacific 747 – Angelo DeSantis

Boeing Dreamlifter – Paul

BAe ATP Freighter – @FlattenedVowel

UPS 757 Nose – Fabricio Jimenez

American 757 Nose – Jonathan

 

Ken Hoke has been flying for over 30 years. He’s currently a Boeing 767 captain flying international routes for a package express airline. In his spare time, he writes the AeroSavvy blog. Follow Ken on Twitter,Facebook, Instagram or Google+.

 



About the Author

Ken Hoke
Ken Hoke has been flying for over 30 years. He’s currently a Boeing 757 & 767 captain flying international routes for a package express airline. In his spare time, he writes AeroSavvy




 
 

 

Fact Time: Wednesday’s Ameristar MD-83 Overrun in Detroit

A chartered Ameristar MD-83 carrying the Michigan men's basketball team overran the runway at Willow Run Airport yesterday. Here are the current facts regarding the accident.
by Phil Derner Jr.
1

 
 

Adult Onset Flight Anxiety – No One Is Immune

Imagine being a seasoned flier with hundreds of flights under your belt and then suddenly finding yourself onboard and terrified. It can, and does, happen.
by Anson Harris
1

 

 

The Rush To Save A Vintage C-53

In a small town 30 minutes outside of Canton, Ohio sits a vintage C-53. If one airline pilot can't raise the money to save it soon, it will meet the scrapper.
by Jay Haapala
2

 
 

OPINION: The Risks of Reducing The FAA’s Control Of Our Aviation Infrastructure

As a new presidential administration prepares to take over, questions loom regarding the future of how the FAA will control the nation's aviation infrastructure.
by David J. Williams
0

 
 

Emirates Arrives at Fort Lauderdale/Hollywood International Airport

Dubai-based Emirates Airline added their 11th destination in the US on Thursday with the opening of the Dubai-Fort Lauderdale route.
by Mark Lawrence
1