A hash of the ash?

The decision to allow aircraft to fly last week was made under humanitarian, economic and political pressure. Let’s hope the new ‘safe’ levels for ash in the air really are safe

Up to teatime last Tuesday, the consensus among those charged with maintaining aircraft safety across Europe was that there was simply no ‘‘safe’’ threshold for the ingestion of volcanic ash into aircraft engines.

David Learmount, Flight International magazine’s safety editor, described the danger: ‘‘The concentrated ash clogs the hot section and abrades the cold section of turbine engines, stopping them or dramatically reducing available engine power.

‘‘Engine core repair following this damage is ...