NEW DELHI (BLOOMBERG) - Pilot error and systemic failures probably led to the crash of an Air India Express jet last year that killed 21 people, investigators said in a report.

The pilot failed to follow a standard "go-around" procedure that discontinues an approach to a potential unsafe landing, India's Aircraft Accident Investigation Bureau (AAIB) said in its report, released on Friday (Sept 10).

In the country's deadliest aviation accident in a decade, a Boeing 737 skidded off the runway at Kozhikode airport in southern India while attempting to land in August last year, and broke apart.

Two crew members and 19 passengers died and 110 were injured.

The Air India Express pilot training programme "lacked effectiveness" and management policies resulted in "deficiencies at various levels causing repeated human error accidents," the AAIB said.

Other contributing factors that cannot be overlooked included a last-minute change of runway and the lack of on-board equipment to help pilots calculate accurate landing data in adverse weather conditions, according to the report.

A large number of similar incidents "reinforce existing systemic failures within the aviation sector", the investigators noted.

"These usually occur due to the prevailing safety culture that gives rise to errors, mistakes and violation of routine tasks performed by people operating within the system."

The crash took place on a so-called tabletop runway, built on a hill. Indian authorities have ignored at least two recommendations in the past decade to install a safety system on such airstrips.

Air India Express did not immediately respond to a request for comment.