Description

On 21 November 2006, an Air Canada Jazz CRJ200 on a scheduled flight from Vancouver to Prince George was cleared for a non-precision approach at destination. During a missed approach because of worse than forecast weather conditions, the crew were unable to retract the flaps from their 45 degree landing setting.

A diversion to the designated alternate was commenced but en route, ATC were requested to provide radar vectors to Fort St. John and an emergency was declared due to an expectation of low fuel on arrival. The aircraft subsequently landed without further problem at Fort St. John with about 500 pounds of fuel remaining, equivalent to less than 10 minutes of flight time.

The Investigation

An Investigation was carried out by the Canadian Transportation Safety Board.

Their findings as to Causes and Contributing Factors were as follows:

1. The maintenance program for Bombardier (CRJ200)flap system actuators in place at the time of the occurrence did not allow for the detection of problems in the flap actuators at an early enough stage to prevent flap failure.
2. The flaps failed at the 45-degree position, increasing drag significantly. The subsequent increase in fuel consumption required the crew to declare an emergency and divert to Fort St. John, which was a closer airport, landing with less than 10 minutes of fuel remaining.
3. A thorough knowledge of the flap system and consistency in the maintenance documentation would have allowed the maintenance personnel to identify and solve the problem sooner.
4. Repetitive flap failures on (the aircraft involved) were the consequence of faulty actuators caused by contamination such as water.

Their findings as to Risk were as follows:

1. Water ingress into the flap system, combined with cold weather operations, is the leading cause of flap system failure on (CRJ200) aircraft.
2. The quick reference handbook (QRH) does not take into consideration the impact of flap failures at 45° following a missed approach. Consequently, the flight crews are not fully aware of the impact it would have on the aircraft climb performance for obstacle clearance or the impact on fuel consumption.
3. There is no cruise performance data available with flaps extended. Therefore, the flight crew could not determine the optimum altitude and speed to attain the best fuel economy.

One other Finding of the Investigation was given. This was “that the practice of recycling a circuit breaker to rectify a problem has inherent risks; however, in this occurrence, it was a reasonable action on the part of the crew.”

Safety Actions taken during the Investigation

A number of safety actions were noted as having been taken during the course of the Investigation:

1. The Operator introduced a new CRJ Fuel Policy Adjustment Policy under which eight airports were identified to be isolated enough to warrant an extra 30 minutes of fuel contingency when the forecast weather is less than 1000 feet and the visibility is 3 miles.
2. The maintenance requirements for CRJ flap systems have been improved.
3. The Operator formalised a process under which any CRJ 100/200 that experienced a flap failure would require senior management approval before the aircraft was returned to service.
4. A review of the Certification Maintenance Requirements (CMRs) for the CRJ flap system, including the overall system design, has been initiated.

Related Articles

• Loss of Control
• Fuel Starvation, Stress, Fatigue and Nonstandard Phraseology (OGHFA SE)

Further Reading

• The TSB Report was published on 25 October 2007 and may be seen in full at /bookshelf/books/837.pdf