US Airlines Runway Excursions Have Been in the News this Winter – How is Business Aviation Doing?
- Dan Boedigheimer
Since a wet or contaminated runway continues to be the most common causal factor in runway excursions, it is not a surprise to see an increase in them during the winter months. US Part 121 airlines had an increase in number of excursions this winter. Southwest Airlines had 2 runway excursions within nearly a month of each other (Burbank in December and Omaha in January). United Airlines had an aircraft skid off the runway at O’Hare in January. United Express (CommutAir) had what was initially reported as an excursion in Presque Isle, ME in March. That incident turned out to actually be a landing between the runway and taxiway.
During that same time frame (December 2018 – March 2019) there have been 10 runway excursions for business aviation aircraft in the United States. Four of those excursions happened within a week of each other (February 5th – 11th). The common theme in those excursions was a wet or contaminated runway.
- Beechjet Richmond, IN. NOTAM for Runway Condition Code (RwyCC) 3/3/3 with 2” of snow on the runway. Runway 5500 feet long. Landed with a 4 knot tailwind with 1 mile visibility.
- Citation 550 Washington County, PA. Wet non-grooved 5000 foot runway. METAR 24014G35KT 4SM +RA.
- Lear 35 Waukesha, WI. RwyCC 1/1/1 (ICE).
- King Air 300 Mankato, MN. RwyCC 1/1/1 (ICE). Takeoff excursion.
We don’t know the causal factors associated with these recent runway excursions, but we still can consider the conditions that were present at the time and evaluate how you might mitigate the risk of operations on a contaminated runway in the future.
Some Items To Consider
What is your contaminated runway policy?
I have not seen a business aviation operations manual that allows for operations on a runway with a RwyCC of 0 (braking action Nil). With the introduction of the Runway Condition Assessment Matrix (RCAM) in October 2017, a RwyCC of 0 would NOTAM close a runway anyway. What is your policy about takeoff and landing with a RwyCC of 1 or 3 (conditions present in the excursions in February 2019)?
Would you land or takeoff on a runway with a RwyCC 1 (braking action poor)? If not, do your coworkers share that risk tolerance? If so, which of the following risk mitigation techniques would you use?
- Determine how to calculate performance on a contaminated runway for RwyCC levels. FAA SAFO 19001 suggests use of a multiplier of between 3 and 5 to your AFM dry unfactored data for a RwyCC of 1 if manufacturer or performance provider data is not available for contaminated runways.
- Add an additional factor to your landing distance. What factor would you use? The FAA recommends at least an additional 15% (Advisory Circular 91-79A).
- Limit tailwind component to 0 and crosswind factor to 25% of demonstrated maximum.
- Get a wind update on final through a report or visual on windsock rather than rely on a weather report you received prior to top of decent.
- Validate when the FICON NOTAM for RwyCC 1 was published and if conditions are likely to have improved or worsened since then based on the weather conditions.
- Minimum ceiling and visibility so you can visually acquire the runway with time to evaluate conditions.
- Call the airport manager or FBO to get a report on ramp conditions. The runway may have a RwyCC 1, but how about the taxiway and ramp? Are they safe to be operating on?
- Have a briefed plan on use of reverse thrust for a contingency plan if one fails or if they don’t deploy at the same time, resulting in asymmetrical braking.
- Has your Flight Risk Assessment Tool (FRAT) been updated for the RCAM values? What impact does or should a RwyCC 1 have on your FRAT?
Do you conduct time of arrival landing distance assessments?
In March 2019, the FAA published Safety Alert for Operators (SAFO) 19001 Landing Performance Assessments at Time of Arrival. The SAFO reminds us that although there is no specific regulation requiring reassessment of landing distance requirements at time of arrival, the FAA encourages the use of an assessment to ensure that a safe landing can be made. Regarding timeliness of performance calculations and weather, the SAFO says “A number of overruns have occurred when pilots were provided with a runway condition that was no longer reliable given changes in meteorological conditions.”
If your risk management technique for dealing with snow packed and icy runways is to celebrate the arrival of spring, don’t think the risk of a runway excursion goes away with warmer weather. We see another increase in excursions during the summer months. The threat does not go away, it just changes.
Dynamic wind conditions on wet runways becomes the most common causal factor in summertime excursions. Consider your operations near convective activity in the terminal area. Thunderstorm avoidance can drive you to select a runway with a slight tailwind which, because of the rapidly changing wind conditions, becomes a significant tailwind upon touchdown.
Add an un-grooved or non-Porous Friction Course overlay (PFC) runway and you have the trifecta of hazards for a warm weather runway excursion. FAA SAFO 15009 Turbojet Braking Performance on Wet Runways reminds us that on an un-grooved or non-PFC runway, wheel braking may be degraded when the runway is very wet. If active moderate or heavy precipitation exists (or has recently passed over the airport), you should be extra conservative in your time-of-arrival assessment.
Advanced Aircrew Academy offers an eLearning module on Runway Excursions highlighting the top 10 reasons for runway excursions in business aviation today. To check out the Top 10 based on actual recent business aviation runway excursions, enroll in the Runway Excursion training today.