Clear sky conditions in place, possible development of ice formations

Clear sky conditions in place, possible development of ice formations

In the world of aviation, making informed decisions is crucial, especially when it comes to Instrument Flight Rules (IFR) flying in cold weather. This was the case for a recent flight from Houghton, MI (KCMX) to Eau Claire, WI (KEAU) in a Cessna 182, a plane not equipped for icing conditions.

Pilots must adhere to strict guidelines to ensure safety, as outlined by the Federal Aviation Regulations (FAR). For instance, FAR Part 91 and IFR Operations prohibit flying under IFR into known or forecast icing conditions without approved ice protection equipment, as stated in Section 91.209. Commercial and charter flights, governed by FAR Part 121 and 135, have detailed requirements for operating in icing conditions.

The aircraft's capability is another key consideration. Without ice protection systems, the aircraft is not certified for flight in icing conditions. Even with de-ice and anti-ice systems, these may have limitations, such as effectiveness at certain altitudes or in specific types of icing conditions.

Weather forecasting and monitoring are essential for safe flying. Pilots should obtain detailed weather forecasts and updates from reliable sources, such as the National Weather Service or Flight Service Stations, specifically for the flight route. Onboard weather radar can also help identify hazardous weather conditions, including icing.

Route planning and decision-making are vital. Pilots should plan routes to avoid areas with known or forecast icing conditions, use wind and altitude changes to minimise exposure, and always have a plan for diverting to a safe location if icing conditions are unexpectedly encountered.

Determining the probability of icing conditions involves using advanced weather forecasting models, collaborating with meteorological services, monitoring real-time weather data, and using PIREPs from other aircraft.

In the case of the Cessna 182 flight, the freezing level extended all the way down to the surface at KCMX, with a temperature of 27 degrees Fahrenheit (-3 degrees Celsius). There was no precipitation reported along the route, but the probability of icing at 3,000 feet MSL along the route mimicked the AIRMET for IFR conditions.

The pilot, an instrument-rated private pilot, needed to file a longer route around the Southeast of the IFR conditions at the enroute mid-point, adding an extra 30-40 miles to the route. The enroute weather conditions had clear skies on the back-half of the route. However, the lowest weather conditions seemed to be isolated around the mid-point of the route, in a 60-mile-wide cluster. To avoid these conditions, the pilot might need to file a plan with a waypoint at the Y55 airport.

Under IFR, the pilot needed enough fuel to fly to the destination, from the destination to the alternate (if required), and for an additional 45 minutes at normal cruise speed. If the weather at the destination did not meet certain visibility and ceiling requirements within an hour before or after ETA, an alternate airport needed to be filed.

The pilot's analysis of weather products and forecasts in comparison to the flight route, altitude, and time determines whether a flight is safe and legal. In 2009, the FAA revised the definition of icing conditions, leaving much of the decision-making to individual pilots.

If flying VFR, the pilot might encounter icing conditions on the initial climb through the clouds and would be scud-running until clear skies are reached. To the East/Southeast of the route, there was a low probability of icing conditions.

The FAA will evaluate all weather information available to the pilot during an investigation, considering if the pilot's pre-flight planning accounted for the possibility of ice formation, alternative courses of action, and steps taken to exit known icing conditions.

1. In the aviation industry, following strict guidelines is essential for safety, as outlined by the Federal Aviation Regulations (FAR), such as the prohibition of flying under IFR into known or forecast icing conditions without approved ice protection equipment.
2. When flying a Cessna 182 or any aircraft without ice protection systems, it is not certified for flight in icing conditions, even with de-ice and anti-ice systems that may have limitations.
3. Weather forecasting and monitoring are crucial for safe flying, as pilots should obtain detailed weather forecasts and updates from reliable sources like the National Weather Service or Flight Service Stations.
4. Route planning and decision-making are vital for avoiding areas with known or forecast icing conditions, using wind and altitude changes to minimize exposure, and always having a plan for diverting to a safe location if icing conditions are encountered.
5. Determining the probability of icing conditions involves using advanced weather forecasting models, collaborating with meteorological services, monitoring real-time weather data, and using PIREPs from other aircraft.
6. If flying Instrument Flight Rules (IFR), the pilot should file a longer route around the Southeast of the IFR conditions at the enroute mid-point, adding an extra 30-40 miles to the route, and should prepare for an additional 45 minutes of flight time.
7. The FAA will evaluate all weather information available to the pilot during an investigation, considering if the pilot's pre-flight planning accounted for the possibility of ice formation, alternative courses of action, and steps taken to exit known icing conditions.
8. If flying Visual Flight Rules (VFR), the pilot might encounter icing conditions on the initial climb through the clouds and would be scud-running until clear skies are reached, with a lower probability of icing conditions to the East/Southeast of the route.

Read also: