it might end up here,

at Delta Technical Operations in Atlanta.

At nearly 3 million square feet,

it's the biggest aircraft repair shop in North America.

Here, mechanics, technicians, and engineers

fix nearly 1,000 planes a year,

with all kinds of issues,

from a loose screw to an engine failure.

But it takes a lot more than elbow grease

to get a plane back in the air.

This is a bustling, and expensive, 24-hour operation.

Cedric Morris: The work never stops

because the planes never stop.

Narrator: That's Cedric.

Back in February, before COVID-19 was declared a pandemic,

he took us behind the scenes

of Delta's massive airplane hospital.

Morris: Let me put my bump cap on.

I look like somebody.

Narrator: Delta TechOps is a maintenance, repair,

and overhaul, or MRO, business.

Morris: We do everything that you see on that aircraft.

We have component maintenance,

engine maintenance, and aircraft maintenance.

Narrator: 6,000 technicians can fix every inch

of pretty much any commercial jet on the planet,

from 150 other airlines, government organizations,

and even military branches.

Morris: Our job is basically

just to maintain the aircraft, keep them safe.

Narrator: An aircraft ends up here

if it's scheduled for maintenance or if something is wrong.

And one of the biggest issues the team deals with

is engine repairs.

When that happens, there's $32 million on the line.

First, a plane is grounded

and then tugged into this giant hangar.

Morris: We can have six wide bodies

and six narrow bodies in simultaneously.

So that's a lot of work

that can be done in here at the same time.

Narrator: Technicians run a diagnosis

for an engine problem.

If they determine it needs fixing,

it heads to the engine shop.

This division of TechOps started in 1961,

at the beginning of the jet age.

Today, engine repair is the most expensive section

of TechOps, with $100 million

in new facilities just in the last two years.

Ray Romesburg: So, the engines come into our shop,

and we take the engines apart completely.

We inspect the parts,

and anything that we find wrong with them,

we are able to repair those things

before putting them back into the engine.

These are very high-valued parts,

so repairing them is the most economical way

to keep our engines flying.

Narrator: Before parts can be fixed up,

they get a chemical bath.

Morris: So, most of the engine parts

are cleaned in this area.

If there's any contaminants on the blades

or any of the parts of the aircraft,

you want to make sure that's removed

so you can get maximum performance of the engine

because of the airflow.

I used to work back here many years ago.

I started back here.

Narrator: Next, the engine heads to one of seven bays

in the engine shop.

Morris: What's going on?

How you doing?

Why's everybody got a smile on their face?

That's what I wanna know.

Y'all act like y'all happy.

Technician: Look where we at, man!

Morris: How you doing?

Technician: Hey, how's it going, buddy? You doing OK?

Narrator: Here, FAA-licensed technicians

work on and reassemble the engine.

Matthew Jackson: We have approximately 900 engines a year

come through for various levels of maintenance.

Narrator: Those cover 14 different kinds of engines.

Jackson: I want to show everybody a BR715 engine.

So, this engine in particular

is undergoing light maintenance,

where it doesn't get fully disassembled.

Narrator: Light maintenance takes anywhere

from 15 to 35 days.

Heavy maintenance, on the other hand...

Jackson: That's where we'd fully disassemble the engine,

go into the internal areas of the engine,

and basically refurbish the entire components

associated with the engine.

Narrator: That can take over two months.

Jackson: 2,000-piece parts that have to be

individually inspected and maintained.

This engine is flying approximately five times a day.

An engine remains on wing from anywhere

from a few years to, some of our engine types,

as many as seven, eight, or nine years.

So we want to take the opportunity while they're here

to do everything that we can

to ensure that they're reliable for the fleet.

Narrator: If an engine can stay in the air longer,

it saves Delta and its customers money.

Remember, these things are expensive,

and so are all the parts that go into them.

This part costs $12,000.

Jackson: And there's 80 of them.

Narrator: Add in price of the surrounding parts, and...

Jackson: We're looking at about $2.2 million

sitting on the table.

This is the highest technology portion of the engine.

These blades operate at very high temperatures

and very high stresses.

Narrator: These fan blades...

Jackson: Out of the latest generation

Rolls-Royce Trent engines.

Narrator: Are made of precious metals and alloys

and cost hundreds of thousands of dollars each.

Jackson: So, a modern jet engine

is worth several million dollars.

The maintenance of those is very, very important

to maintaining the value of that asset.

Narrator: Only about 20%

of all the engines fixed here are Delta's.

The rest are for customers.

Jackson: That's probably UPS right there.

We have Azure, Gol,

Brazil, and Virgin Australia engines.

Narrator: Repairing all these flying beasts

takes a lot of skill and caution.

Morris: Anything can kill you that we touch.

Everything is stronger than us.

Everything is heavier than us.

You have to have your head in the game.

Narrator: You're looking at a 13,000-pound engine.

Morris: Lifting something that heavy,

it requires a lot of safety, coordination,

teamwork, and attention to detail.

Narrator: But an engine that runs smoothly

is just as important.

There's no pulling over on the side of the road

if there's a problem.

They're 40,000 feet in the air, so nothing can go wrong.

Jackson: But it's an example of the precision

and the very close tolerances

that everything has to be built to,

because of how fast it all spins and how hot it all gets.

Morris: We want you to get to your destination safely.

And that's what this is all about.

Narrator: To keep track of the thousands

of repairs and checks, technicians record

every step of the disassembly, assembly,

and inspection process on work cards.

They also rely on fancy gear,

from the laser welding equipment to the turbine grinder.

Jackson: That precision is necessary

to ensure the efficiency of the engine

when we return it to service.

Narrator: All this new equipment also means

Delta can repair some of the most technologically advanced

commercial engines in the world.

That happens out in the newer facility, opened in 2018.

Once technicians have restored all the parts,

they converge back into one of the engine bays.

Here, they flip the engine vertically

and start reassembling it.

Jackson: The core engine is complete at this point,

and they're putting on all of those

accessories and harnesses

and piping on the outside of the engine.

Narrator: But before an engine can go back on a wing,

there's one more step.

Quality testing.

That happens at the world's largest engine test cell,

a short drive or a bike ride from the engine shops.

Ken Edwards: You don't want to encounter problems

while you're installing an engine on-wing.

So it comes to us, and we make sure everything's

passed off and clear.

This part of the building is where the engines come in.

We install and rig the engine.

So, basically, we put the test equipment on the engine

and get it ready for it to run.

And then this part of the engine

is your actual test chamber.

Narrator: The test chamber is the newest addition

to TechOps and where the engines are test run.

It can handle 150,000 pounds of thrust,

even though no engine actually has that kind of power.

Engineers run tests 24/7,

monitoring engine performance from the control room.

Edwards: The reason we need 24/7

is because of the production coming out of the shops.

So, I can have three engines prepped and ready,

but I got one test chamber.

So, you know, we want to keep that test chamber running

and keep it moving.

So you want to get it in there, get it run,

get it back out so we can move our next engine in.

Narrator: Once Ken's team signs off on the new engine,

it's carted back to the hangar,

secured on the wing, and tugged out for takeoff.

Morris: As you see, there's a lot of things going on

behind the scenes at the maintenance program.

We're always constantly trying to work

to make sure we're safe, effective,

and proficient at what we do.

That means once we get an aircraft in here,

we're trying to make sure that we take care

of everything that we need to take care of

while it's down, so it can get out and fly.

And when it comes back, we'll do it all over again.

Abby Narishkin: Hey, guys, my name's Abby.

I'm the producer on this video.

Since we visited TechOps back in February,

obviously things have changed a lot,

and TechOps has been operating this whole time,

but things look a little different.

Mandatory temperature checks, PPE,

and social distancing on the floor.

But I know a lot of big businesses

are changing with the times.

So let me know what you want to see

in the next episode of "Big Business,"

and make sure to hit the subscribe button

so you don't miss out.