April 29, 2020

CFM56–3/5 Water Wash Experience

The current breakdown affected 97% of the global airtransport market. With 65% of the global fleet currently grounded, most airlines are running at 10–15% capacity. Others have totally stopped their operations or accomplish humanitarian or repatriation flights only.

Based on a 3-month lockdown period globally, we expect that May-June shall bring back some operators to operating limited routes. Taking into consideration that the aircraft are parked for a couple of months and some airlines have a lack of engine covers or even proper preservation, some new defects and tangible engine parameters deterioration may be expected after resuming the operations.

For the last couple of weeks our teams both in Ukraine and in the UAE observed couple of local sand and dust storms. And such weather activity is not only common for our regions but may happen anywhere in the world. Therefore, the engine wash may seem a very good idea prior returning to service.

The usual engine deterioration may be slowed down if the gas path is washed regularly. As an example, each CFM56–5B wash may recover HDTGM by 10–15˚C on average. Consequently, the fuel consumption may be improved by 0.35% as per OEM research. And this is the example of the parameter’s amelioration for the engine in operation. The benefit for an engine that was grounded for two-three months and affected by sand/dust storm will be much more significant provided that the water wash is performed before the first engine start. This helps to remove dirt particles from compressors blades/vanes and what is much more important from turbine nozzles and blades to avoid further cooling holes blockage with melted dust.

There are some types of specific wash equipment and different methods of water injection. As per our teams’ latest experience gained in different engine types, injection with J-hook shaped probes gives the best results and requires less water amount due to the fan blades are avoided and all water flows exactly into HPC inlet.

It is very important to strictly follow the correspondent OEM’s recommendations during the water wash procedures and the consecutive engine runs in order to purge water out of the air bleed system properly especially if the powder detergent is used.

Our engine team is ready to give you proper advice and offer support in a framework of CFM56–3/5 engines while looking for the soonest restart of aviation operations around the globe.

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