UK regulators have tightened their processes for detecting safety-related problems with operators, after an overrun incident involving a freight carrier showed that close scrutiny had failed to reveal the full extent of operational deficiencies.

The Civil Aviation Authority suspended Emerald Airways' air operator's certificate in May 2006, but at the time did not disclose the full reason for the decision. But an Air Accidents Investigation Branch inquiry, published yesterday, details a British Aerospace 748 overrun at Guernsey, two months earlier, which highlighted serious inadequacies at the carrier.

Although the CAA had monitored Emerald for more than two years, the AAIB says that, until this incident, the scrutiny had not shown up the "depth of the lack of knowledge" of standard procedures within Emerald's flight operations department.

The CAA has since introduced a "more robust" process of measures to address identified safety-related shortcomings in carrier operations. It has put in place an 'on notice' scheme which warns carriers of a downward trend in safety performance which could lead to operating restrictions and even suspension of operating certificates.

"These measures have already been used effectively on several occasions," says the CAA. "We believe these measures, together with the existing oversight system, provide the graduated system needed to ensure that operators maintain the required standards."

Emerald's 748 had been conducting a Category I instrument landing system approach to Guernsey's runway 27 on 8 March 2006. But investigators state the crew "delayed significantly" the decision to land beyond the intersection of the ILS glideslope and the decision height. The delayed decision meant the aircraft landed far beyond the touchdown zone, with just 400-550m (1,300-1,800ft) of remaining runway.

"The commander did not immediately appreciate how far down the runway he had landed and delayed applying maximum braking until he saw the end of the runway," says the AAIB.

It adds that, contrary to standard procedures, fine-pitch stops were not withdrawn after landing which meant the aircraft did not obtain maximum braking benefit from the propellers.

Despite an available landing distance of 1,453m the 748 overran the runway end by around 145m. The AAIB says the captain did not properly brief the co-pilot on the approach, and the co-pilot did not challenge the non-standard operating procedures employed. None of those on board was injured.

Source: Air Transport Intelligence news