RAPID ENGINE-OIL loss on both engines forced a British
Midland Airways
Boeing 737-400 crew to make an emergency landing at
London Luton Airport on 23 February.
UK Civil Aviation Authority records show that blanking plates had not been replaced after borescope inspections of the two engines, and that this led to oil loss.
The UK Air Accident Investigation Branch is to conduct a "formal investigation". The airline says that it has temporarily suspended three maintenance engineers while an internal probe is completed.
The incident started as the aircraft climbed out from
East Midlands Airport for
Lanzarote, Canary Islands, with 177 passengers and six crew. When low-oil-pressure warnings for both engines were received at 12:08, the crew declared a full emergency and landed the aircraft safely at 12:14, shutting down the engines immediately upon stopping. Each engine is said to have had 1.5litres (0.3gal) of oil remaining of the normal 22litres.
This particular incident together with similar occurrences led to the Part 145.A.65 critical task requirement to ensure that different mechanics carry out the same task on oil or fuel system engine servicing on twin and multi engine types.
Additionally, it is a requirement to plan maintenance to stagger engine servicing or inspections where possible, for example carry out boroscope inspections at separate intervals.
Maintenance Organisations should have critical task control policies, these should require a second Duplicate Inspection on tasks that are deemed to require a further safety check, these may include tasks carried out during the small hours at night, listed tasks such as windscreen changes, gear changes and so on.
Despite these precautions I am aware of several incidents that have occurred during the past couple of years,
Citation take off with elevator trim reverse rigged.
Bombardier Global windscreen bolts not correctly torqued and water ingress to the cockpit.
Citation off maintenance with speed tape over static ports.
Cessna Mustang take off with NACA duct taped over following aircraft washing, negative pressure in fuel tanks and engine flame out due to fuel starvation, following emergency landing aircraft written off due to structural damage.
Challenger engine cowling not properly fitted and leaves aircraft after take off.
Rubber wing walk mat left on Challenger wing and goes down intake during take off and damages engine.
Despite MROs recognising the safety situation there are still maintenance related incidents.