Recommendations Follow Accident During Swinging Load Test Conducted In December, 2012

The FAA has issued a Safety Alert For Operators (SAFO) highlighting current guidance and best-practices for part 133 operators who conduct external-load operations with non-human external cargo (NHEC).

The SAFO is in response to an accident which occurred on December 15, 2012. A helicopter was conducting external-load operations under part 133 with a synthetic external-load line with no swivel device in use between the NHEC and the external-load line. During forward flight the continuously spinning load was inadvertently released due to a severed external-load line. The remaining external-load line then became entangled in the tail rotor. The helicopter impacted terrain, which caused substantial damage to the helicopter and serious injury to the pilot.

According to the SAFO, certain external loads have a tendency to rotate in flight, either intermittently or in the form of a sustained spin. The overall effects generally become more pronounced with an increase in the helicopter’s speed. Without a swivel device placed in the load configuration, twisting of the line due to a spinning load could cause damage to the rigging, damage to the aircraft, and/or inadvertent release of the load. Damage could be exacerbated by nonmetal-to-metal at the attachment point. Use of a swivel allows the load to rotate freely in flight without twisting the line and also limits the torsional strain on the hook assembly. In load configurations with multiple net loads, swivels allow each net load to rotate independently in flight. If the load cannot be configured to prevent spinning, a swivel should be used whenever practical and circumstances dictate.

The FAA recommends that Part 133 operators who conduct external-load operations with NHEC should include consideration for the appropriate control of spinning loads in the information section of the Rotorcraft-Load Combination Flight Manual required by § 133.47(c) and in standard operating procedures (SOP). The operator’s procedures should provide the following guidelines:

• Pilots and ground personnel should be thoroughly trained and briefed.
• Equipment used in cargo rigging should be properly inspected and maintained.
• When rigging new loads, new load configurations, multiple net loads, or loads known to rotate in flight, the use of a swivel device should be considered.
• A swivel may not be needed or warranted, such as on certain specialized loads or when utilizing a swiveling cargo hook.

The FAA says that operators should include this SAFO in initial and recurrent training programs for pilots and ground personnel.

FMI: www.faa.gov