What it takes to change the gigantic A350 engine
Our second oldest A350, OH-LWB got one of her engines changed at the end of November. We interviewed Reijo Katiska, Powerplant Engineer at Finnair who shares insights about the process of getting the impressive and gigantic 8,000-kilo masterpiece changed.
The first, long-awaited A350 aircraft arrived to Finnair six years ago at the end of 2015. The gorgeous and modern A350s have massive Rolls Royce engines. Reijo Katiska, Powerplant Engineer at Finnair, is responsible for ensuring that the mechanics follow the manufacturer’s instructions and guidelines to maintain the airworthiness of the aircraft and ensure maximum safety.
Why is the engine changed?
There are both scheduled and unscheduled engine changes. The reason for an unscheduled engine replacement is a fault-finding whereupon the engine must be removed to fix the fault. This one, however, was a scheduled engine change.
The disconnected engine is sent to Germany, where the specialised mechanics take it apart and check the parts carefully. After six months, it returns to us. Now, this might sound like an awfully long time, but the humongous engine is three meters in diameter and weighs about 8,000 kilos, so you can only imagine how many different parts it contains.
How often should the engine be changed?
The answer to this question is not so simple, as the A350's engine is still a relatively new product that is monitored closely. The current estimate is that the engine should be replaced and sent for inspection approximately every 5 to 6 years.
During the manufacturing of the engine, a certain service life span has been defined for the rotating parts or so-called life-limited parts of the engine. This has been determined by the authorities to ensure airworthiness and flight safety. Parts need to be inspected and replaced at the end of their service life.
The lifespan of the engine parts is calculated in cycles, which, in turn, have traditionally been calculated in flight volumes. However, for the Rolls Royce engines, the consumption is monitored more closely, and an enormous amount of data is collected from the actual load on each flight, which can be used to calculate parts wear and optimise the timing of engine replacement.
The most burdensome thing for the engine is takeoff. Finnair's pilots are extremely skilful with takeoffs taking into account, for instance, the runway and weather conditions exemplary. Rolls Royce is very appreciative of this.
What does an engine change require?
Finnair's skilled mechanics change the engine in two-shift teams of about eight people. There are many phases included in removing and replacing the engine, and both very specific skills and more general knowledge are required for the different phases.
So far there have been different kinds of teams changing the engine. This time the team consisted of both very experienced as well as newcomers, in order to span the knowledge further. Soon, due to the amount of our fleet, there will be an estimated 10 engine changes each year.
This engine change was scheduled to last for four days. This included engine preservation, removing the required parts, removing the engine itself, putting the replacement engine in place, attaching the required parts and testing the engine at the end.
In the future, the aim is to change the A350 engine in two days. This will not be too big of a challenge, however, as the current record for our skilled employees is 39 hours!
Images by Finnair Technical Operation / Ossi Heino