Flexibility is the Key to Safety… and Happiness

 

Thunderstorm Microburst

Microbursts from thunderstorms can produce winds greater than 100 knots.

 

By Captain Judy Rice

The Citation was at FL370 (37000’) while a thunderstorm was seen building in the distance. It was amazing to watch and feel this energy from a far distance. The cumulonimbus clouds were building higher than the jet’s altitude. The lightning brightened the darkening sky.

 

Are thunderstorms really all that dangerous?

Thunderstorms are part of summer weather in Florida, as most pilots here know. Thunderstorms are one of nature’s most powerful forces and a weather hazard that are dangerous for all pilots. Flying too close to these powerful beasts can end in disaster. Pilots should understand these and all-weather hazards, know how to avoid their dangerous conditions, and safely make a go-or-no-go decision.

 

The destructive forces of thunderstorms occur within the storm itself as well as surrounding areas. Severe weather from convective systems can include some or all of the following hazards: extremely heavy rain, strong wind shear, large hail, and severe turbulence. According to the Aeronautical Information Manual (AIM), the visible thunderstorm cloud is only a portion of a turbulent system with updrafts and downdrafts often extending far beyond the visible storm cloud. Severe turbulence can be expected up to 20 miles from thunderstorms.

 

Can radar help pilots avoid thunderstorms?

Every pilot’s preflight should involve a careful review of weather that includes SIGMETs and Convective SIGMETs. SIGMET information includes severe turbulence, and Convective SIGMETs provide information on line, area, embedded, or severe thunderstorms.

 

Inflight weather depiction equipment provides valuable tools for pilots, but there are limitations a pilot must understand. One example of these limitations is that the Nexrad weather radar images update approximately every five minutes. Five minutes for a fast moving, rapidly developing thunderstorm can bring dramatic changes that a pilot may not receive until the next radar image updates. In addition, radar images depict areas of precipitation, not turbulence. Weaving between the colored blotches on the moving map has the potential for turbulence beyond you and your airplane’s capabilities with possible disastrous results. Never regard a thunderstorm as a minor threat, even when radar echoes are showing light intensity.

 

What if a thunderstorm impacts flight plans?

As a new pilot, my one experience avoiding a thunderstorm taught me that Get-There-Itis was not the safest, best choice. Get-There-Itis is the decision for continuing to your planned destination even when risky alternatives exist. These goal fixations can present serious flight safety issues. It is important for a pilot to understand and recognize Get-There-Itis before compromising safety.

 

I had checked weather before the long cross-country with thunderstorms reported long after my return. Nearing my destination, I grew concerned when noticing cumulus clouds building. Calling Air Traffic Control (ATC) reaffirmed my concerns. ATC offered to vector me through the storm clouds allowing me to land as planned. I accepted the offer and remained clear of clouds, but at times it was difficult to maintain control of the airplane due to the turbulence. After landing, I had the airplane inspected for damage and vowed to always remain a safe distance from thunderstorms and to avoid Get-There-Itis.

 

What is the best way to avoid thunderstorms?

Avoiding thunderstorms is the best policy. According to the FAA Advisory Circular (AC 00-24C), the following list provides some Dos and Don’ts for thunderstorm avoidance:

  • Don’t land or takeoff in the face of an approaching thunderstorm.
  • Don’t attempt to fly under a thunderstorm.
  • Don’t trust the outside visual appearance as an indicator for turbulence.
  • Don’t assume air traffic control will provide deviations around thunderstorms.
  • Don’t rely on inflight weather radar imagery for negotiating a path through a thunderstorm area.
  • Do listen to ATC frequencies for Pilot Weather Reports (PIREP) and aircraft requesting deviations or diversions.
  • Do ask ATC for radar navigation guidance or to approve deviations around thunderstorms.
  • Do use Inflight Weather Advisory Services (AIM Chapter 7-1-6).
  • Do divert and wait out the thunderstorms on the ground if unable to navigate safely around an area of thunderstorms.

 

Happy, safe pilots are flexible with their schedules, avoiding the trap of Get-There-Itis. Nature’s fireworks are best enjoyed with the airplane safely secured on the ground while having a cup of coffee.