The “Barn Door” Effect

- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner
Monday, 18 January 2010
Charles A. West, NOAA/NWS, Hampton, GA

Handout (412.2 kB)

When enroute and at altitude, commercial aircraft pilots will deviate around convective weather more than five nautical miles for severe weather and lightning avoidance. These same pilots, given a situation where a similar storm is on final approach to their destination airport, will usually fly underneath a heavy to extreme convective cell with tops in excess of 50kft. These cells can and usually do have the potential to produce severe weather including excessive lightning, wind shear, microburst, hail, and occasionally tornadic activity. Most pilots approaching major airports will continue their approach in these conditions usually because the aircraft in front of them had done it successfully, and that they can see their final destination or the “Barn Door”. Not until a pilot in command reaches their safety threshold and executes a missed approach and flies away from these conditions, will this dangerous process end. This study shows forecast products and recommends air traffic management procedures that will help mitigate the potential for future aircraft disasters in final approach convective conditions.

These findings and views are those of the author and do not necessarily reflect the views of the National Weather Service.