A Flight Risk Assessment Tool For BizAv, Part 3

Helicopter operations are distinctly different from fixed-wing, and a Flight Risk Assessment Tool (FRAT) should be modified for the helicopter’s operating environment.

Two clear areas in which a FRAT for helicopters should be modified are off-airport landing zones and the risk from deteriorating weather. Unfortunately, both of contain a preponderance of unknown information that complicates flight risk assessment.

The threats at off-airport landing zones often include multiple unknowns to include surface conditions, slope, lack of accurate wind information,  and proximate obstacles such as trees, light posts, bushes, high grass, fences, buildings, vehicles, people, livestock, and almost-impossible-to-see thin wires.

It is standard risk assessment practice to establish a “high recon” orbit to perform an in-depth analysis of an off-airport landing zone. The altitude, airspeed and flight pattern for the high recon will be governed by terrain and wind.

A commonly used acronym to remind a pilot of the necessary items to analyze is known as the AWOTFEEL check. It stands for: estimated Altitude of landing zone, Wind, Obstructions, Turbulence, Forced landing areas, Entry, Exit, and Landing zone conditions. Once the pilot is satisfied that each of these critical parameters is safe, then a low orbit is conducted to do a closer evaluation of the landing approach and touchdown zone.

Companies that conduct flight operations in mountainous and snow-covered terrain have revised their risk controls. Pilots at Air Zermatt and heli-skiing operators are mentored by avalanche control specialists to learn about differences in snow composition, snow metamorphosis over time, how winds on windward zones will tend to remove snow from a ridgeline and deposit it in the leeward side, how snow on a southern-facing aspect will metamorphose differently than a north-facing slope, etc.  

A knowledge of the recent weather pattern is vital too. A warm spell during the daytime followed by cold temperatures at night will tend to form a crust on the surface of the snow.   Yet a fresh snowfall on top of such a crust, especially if the snowfall is light powder, will create a double threat. The loose powder will quickly create a “white out” as soon as the rotor wash hits the surface, and once the helicopter finally settles onto the surface, the skids can get “caught” by punching through the underlying crust, creating the potential for a dynamic roll-over.

Several of these operators collaborate in training with first responders and ski patrol teams with the goal of elevating the skills of team members on the ground to better evaluate a potential landing spot for a rescue helicopter prior to a helicopter’s landing approach.

Another high risk condition that has been problematic for helicopters is deteriorating weather.  A 1988 NTSB study determined that the single most common factor in fatal EMS helicopter accidents was unplanned entry into instrument meteorological conditions and most of these accidents occurred at night. During the preflight planning stage pilots seldom had exact weather information for the destination.

Pilot decision making was also complicated with weather forecasts containing “chance of localized weather” conditions. Many air ambulance flights are to remote landing sites or to hospitals that do not have such weather reporting available.

This places a premium on a  pilot’s ability to apply meteorological knowledge, trying to assess the influence of nearby water bodies, diurnal heating and cooling, the influence of topography, incoming weather fronts, etc., all of which can have a localized effect on the weather.  

This introduces a significant challenge to a pilot, and realistically requires constant re-evaluation during the flight. Some organizations have implemented formal “go no further” criteria in the form of airspeed reduction and/or height reduction in reaction to worsening weather.

For SMS purposes the utilization of an Enroute Decision Point by a flight crew should be recorded for evaluation of the effectiveness of the implemented risk control strategies. By the way, this would integrate well into an SMS if your program has an Aviation Safety Action Program as well as Flight Data Monitoring.

Importance Of Timely Re-evaluation

Once you have custom designed your own FRAT, consider utilizing a color coding system to help users quickly identify which flights fall into the acceptable (green), additional mitigation required (yellow), or unacceptable (red) levels of cumulative risk. This will help to prioritize the flights that require mitigations by the pilots, dispatchers and aviation managers.

A tool is only productive if it is actually used, and that requires being user friendly. Some of the commercially available FRAT programs automatically input important weather, terrain and runway conditions data prior to a flight. Pilots complete the FRAT by answering questions on their fitness that can be easily entered via a smartphone or tablet.  

Several of these products automatically re-score the FRAT one hour before departure with updates in the winds and weather. The tool will alert the pilots if there is a change that could negatively affect the flight’s risk.

Many times, the approach and runway surface conditions change during a flight due to quick moving or convective weather. Professional pilots should be proficient in conducting a landing performance assessment to detect these changes from the preflight planning data and apply prudent risk mitigation for any significant changes.

A FRAT’s effectiveness can be increased when a dispatcher actively follows a flight because they have important information such as the latest information on the runway surface condition, weather and winds, as well as the software to quickly recompute the fuel needed for diversion to a suitable alternate.  

Dispatchers readily have the software to compute the new landing distances, and/or do the calculations for the crosswind component not only for the original destination but for re-evaluating the suitability of an alternate.  

What should an operator do if the FRAT score for an individual flight rises into the equivalent of a “yellow” risk category? This is where a flight manager should become involved to propose proper mitigation measures that are consistent with the company’s safety policies.  The intervening actions should be recorded for evaluation of the effectiveness of the implemented risk control strategies as well as for the identification of new hazards.

Additionally, a company should have the proper processes to determine the need for new or revised risk controls. These are key elements of an SMS, which will become mandatory for Part 135 operators by May 28, 2027.

For A Flight Risk Assessment Tool For BizAv, Part 1, click here.

For A Flight Risk Assessment Tool For BizAv, Part 2, click here.