How much Desert Dust do Aircraft Engines Ingest at Major Airports?

Mineral dust is the most abundant aerosol in the atmosphere and in particular regions exists in high concentrations. Ingestion of dust by aircraft engines can result in erosion, corrosion or a build-up of deposits damaging internal components. A move towards more efficient engines over recent years restricts capacity to tolerate detrimental impacts in engines. Air traffic in arid areas such as the Middle East has also increased dust exposure. However, it is not currently known how much dust is ingested by aircraft during take-off and landing. In order to quantify this, the vertical profile of dust is required. Here we present a climatology of vertical profiles of dust from the ECMWF Copernicus Atmospheric Monitoring System (CAMS) reanalysis at 10 major global airports, as well as their seasonal and diurnal variability, between 2003-2020. We evaluate the CAMS dust profiles against spaceborne lidar retrievals of dust from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the CALIPSO satellite using both the standard NASA Level 3 product and the LIdar climatology of Vertical Aerosol Structure (LIVAS) product. Finally, using expected aircraft ascent and descent rates and associated mass flow into an engine, dust dose is calculated for take-off, climb, descent, hold, approach, land and taxi phases, as well as for the entire ascent/descent at different airports, using both CAMS and CALIOP datasets.

We show that vertical distribution of dust varies significantly between airports and across seasons, which has a large impact on the total engine dust ingestion. Diurnal dust variations at some airports such as Dubai are extremely large, with night time surface concentrations reduced by over 20%.  Vertical profiles from CAMS show considerable differences to the standard CALIOP L3 retrievals, though agreement with LIVAS profiles is much better. Aircraft engine dose is found to be highest for Delhi (where dose exceeds 7g for a single descent in summer), Niamey and Dubai. During ascent, ingestion is largest during the take-off phase of flight, such that airports with large concentrations of lower altitude dust incur higher doses. During descent, dose is strongly dependent of the altitude of holding pattern relative to the altitude of maximum dust concentration, such that Delhi and Dubai incur the largest dust dose. Therefore, it is recommended that measures to reduce dust ingestion are airport-specific, and could include practices such as night time take-off and adjustment of holding pattern altitude.