Post-Pandemic Mystery at Heathrow

[akpa1]

https://fearoflanding.com/demystifying/post-pandemic-mystery-at-heathrow/

[h2odragon]

> blocked with something described as “solid soil type material”.

and i said "mud daubers". They sometime blocked up intake or exhaust or PCV ports in idle engines too, and cause some interesting issues until you figure out whats going on