The previous shift had found damage on the nose cowl section of the left engine. This damage is non-repaireable and not allowed according the manuals so the engine cowl has to be replaced. We had an aircraft sitting at the other side of the hangar that was in for a big inspection and didn't need to fly any time soon so the decision to 'rob' the engine cowl of one of this aircrafts engines was pretty obvious.

the damaged engine cowl

My colleague and me get started on removing the good engine cowl from the aircraft at the other side of the hangar while another colleague is driving in from home. He wanted the day off but due to this job now has to come in to work.

We bring the tools that we need for the job over to the aircraft and get the hangar and connect the hoist to the engine cowl.

hoist connected

We move the crane to the correct position without aiding it ourselves because otherwise the engine cowl would 'jump' when the cowl is disconnected. We then take the slack out of the cable's of the hoist because we obiously don't want the engine cowl to drop when we remove the bolts.

hoist ready for lifting

We now need to remove the connecting parts of the engine cowl, first we have to remove the engine anti ice duct. (When the flight crew selects engine anti ice to on, the engine anti ice valve should open and hot bleed air blows into the engine cowl's, through piccolo tubes and out of small escape holes, this heats up the engine cowls and prevents for ice build up on the cowls).

anti-ice duct

There.... 2 clamps and the duct comes right out, I wish everything in life were this easy.

anti-ice duct removed

Next up is the electrical temperature sensor, the T2 sensor.

T2 sensor

This sensor is installed with high vibration mounting to minimize the shaking of the engine on the sensor.

high vibration mounting

The sensor is a part of the engine and not of the engine cowl, therefore on the engine is a mounting plate to install the sensor for shipping.

sensor shipping mount

The sensor is directly in the intake airflow of the engine to measure the temperature most accurately (this temperature is ofcourse important for thrust settings, lower temperature gives a higher thrust at lower N1 rpm, This will all be explained in the 'engine's section on this site). But for now it's important to know that this sensor is installed with aerodynamic sealant.

T2 sensor

We need to break the sealant in order to push the sensor out of it's position to remove it but fortunately my colleague tells me that he has a trick to do this.

tricks of the trade

and he gently pushes the sensor out.

simple enough

We connect this sensor to the engine on the shipping mount.

T2 sensor on shipping mount

With this T2 sensor now removed we now only have a hydromechanical temperature sensor remaining. To remove this one its pretty much the same as the electrical sensor and is removed without much difficulty.

hydromechanical temp sensor

I incorperate my new trick....

hydromech sensor removed

and this sensor is now also out of the cowl and connected to it's shipping mount.

hydromech sensor on shipping mount

My other colleague now arrives and we get right on removing the bolts that connect the cowl to the engine.

spanner on bolt

We remove all of the bolts that hold the cowl to the engine.

nut and bolt

And the cowl comes right off......

removing the engine cowl

We now have to get the engine cowl onto a cart of some sort.

cowl hanging in the air

We hunt around the hangar for a bit and we find a cart that is actually made to transport engine cowls on.
This is what the engine looks like without the engine cowl by the way.

bare engine

My colleague allways seems to be happy when he get's to operate heavy machinery.

Rob with his crane

We put the engine cowl onto the transport platform, wheel it over to the other side of the hangar and hoist it back into another crane and plant it onto the engine.

installing the engine cowl

The engine's electrical generator gets in the way...

engine cowl hitting the generator

And we are mis alligned a bit.

bit too low

But we get there


Here's me tightening bolts.

me tightening bolts

And here's my colleague that had to come from home tightening the other side.
at least he's still smiling.

tommy the voice

There, the bolts are installed, now we need to install the sensors again.

cowl in place

We install the sensors and do a check on the engine, time is now running out if we want to testrun this engine before nightfall. We decide to skip our break and continue to work on the engine.

tommy inspecting the engine

My colleague discovers that there is little or no oil in the starter motor, we need to fill this up later, for now we have to install the fan cowls (the doors that cover the fan case.
In this case, the doors were a bit of pain.

fan case cowls hinging on screwdrivers

The fan cowl doors and behind that are the thrust reverser halfs.

doors open

My colleague removes the thrust reverser locks so that we can close the thrust reverser doors.

thrust reverser door locks

Both my colleagues pumping pressure in the hydraulic actuators to disengage the thrust reverser door lock.
Tommy is still smiling ;-)

thrust reverser door closing

And down it goes...

closing the thrust reverser door

We now have both the engine cowl's installed and the thrust reverser doors closed, we fill the starter motor with oil.
tommy is still smiling...

starter motor oil

We are good on schedule but time is running out for testrunning so we close the doors and prepare for towing and testrunning.


My colleague Rob get's to play with heavy machinery again, this time his favorite one's, jet engine's, at high power.

rob in his groove

We spent more then half an hour running both engine's to complete all the tests that we needed to do and here's a short clip of Rob finishing the last bit of the test running session.

Click play to start.

The aircraft passes the test and we can finish off the job.

rob is happy

We apply some aerodynamic sealant on the sensors.

tommy the sealant master

After 8 hours of work, Tommy get's to put on some more sealant onto the cowling and that should finish our shift for the day, note that he is still smiling.

sealant master at work again

Now that's tight sealing.

slick sealing

The day is at an end, the sealing needs to dry, we finished this job and we can go home. The nightshift get's in. We leave the aircraft outside with just a couple of small job's that needs doing to it.