NTSB Factual Report

On November 22, 2010, about 0929 mountain standard time, an Israel Aircraft Industries Gulfstream 200 airplane, N718QS, was undamaged during a runway overrun at the Jackson Hole Airport (JAC), Jackson, Wyoming. The airplane was registered to Net Jet's Sales Inc., Oklahoma City, Oklahoma, and operated by Net Jets Inc., Columbus, Ohio, under Title 14 Code of Federal Regulations Part 91. The airline transport rated captain, who was the flying pilot and airline transport rated first officer were not injured. Instrument meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the repositioning flight. The cross-country flight originated from Bozeman, Montana, at 0837, with an intended destination of JAC.

In a written statement, the captain reported that earlier in the morning the flight was delayed due to the weather and runway surface friction report values (MU) in the 20s at JAC. About an hour later, the flight crew received company clearance for the flight, noting MU values were in the 40s. Following an uneventful flight, the flight crew received the weather conditions at JAC from the airport's automated terminal information service (ATIS), noting that weather and runway conditions were acceptable for the approach and landing. The flight crew continued the approach to the airport and changed frequencies to the air traffic control tower (ATCT). The captain stated that a previous aircraft on approach reported that they had descended out of the clouds about one and one-half miles from the airport and that runway braking action was fair.

The captain further reported that upon landing on runway 19, they deployed the thrust reversers and noted that all of the ground/air slat indication lights were green and that the anti-skid system began to pulse; however, the airplane was not slowing. The captain said that he applied maximum thrust reverse with no effect on slowing down. As the airplane approached the departure end of runway 19, he realized that the airplane was not going to stop before exiting the end of the runway and initiated a slight turn to the right to avoid runway approach lighting. Subsequently, the airplane came to rest about 25-feet beyond a 338-foot long blast pad.

In a written statement, the first officer reported during the flight to JAC, the flight received delayed vectors for traffic sequencing and obtained runway MU values of 41, 37, and 36, and completed the approach and arrival checklists in addition to calculating landing distances. The first officer stated that about 10 minutes prior to landing on runway 19, the tower reported that runway braking action was a MU reading of 40, 42, and 40. Upon landing, ground airbrakes and thrust reversers were deployed and brakes were applied. The first officer noted that deceleration was slow despite maximum thrust-reverse. Following the runway overrun, the flight crew conducted the after landing and shutdown checklists, and exited the airplane. Upon exiting the airplane the first officer conducted a walk-around, noting no damage and that the airplane was on a hard surface. He then walked to the departure end of runway 19 to evaluate the runway surface conditions and noted that the runway appeared to be covered by clear ice as far down the runway as he could see.

The flight crew reported no mechanical malfunctions or failures with the airplane that would have precluded normal operation.

Review of the ATCT recordings revealed that about 5 minutes 47 seconds prior to the runway overrun, the airport Saab vehicle (vehicle used to take runway friction measurements) operator reported to the ATCT controller that the MU values were 40, 42, and 40, with patchy thin snow over patchy thin packed snow and ice. The flight crew contacted the controller about 54 seconds after the updated runway conditions were reported.

About 3 minutes 48 seconds prior to the runway overrun, a pilot of a Piper Meridian reported the runway was “a little bit slick out here” and that braking action report of was poor to fair. The flight crew of the Gulfstream acknowledged the pilot report 28 seconds later to the ATCT controller. About 1 minute 23 seconds before the runway overrun, the controller informed the crew of the Gulfstream that MU’s were in the 40s, however braking action reports were not quite reflecting that. The crew of The Gulfstream acknowledged the controller's transmission shortly thereafter. The flight crew reported obtaining visual contact about 1.8 miles from the runway at an altitude of 7,000 feet mean sea level (msl). During the landing overrun, the flight crew reported braking action nil to poor.

Review of recordings from the cockpit voice recorder revealed that the flight crew discussed the airport conditions and verified that they had sufficient landing distances. The flight crew estimated that a worst case scenario for landing distance was 5,877 feet with a landing configuration of 40 degrees of flaps, de-ice and anti-ice on.

The Jackson Hole Airport (JAC) features a single 6,300-foot long and 150-foot wide runway, which was paved with porous friction course (PFC) asphalt, and had high-intensity runway edge lighting installed. The runway also had precision instrument markings, medium intensity approach lighting systems (MALS), and precision approach path indicators (PAPI, set at 3 degrees), for operations on both Runway 01 and Runway 19. Runway 19 was equipped with an instrument landing system (ILS). The runway had lighted distance remaining signs, every 1,000 feet, in both directions. Both runway ends had runway safety areas measuring 500 feet by 1,000 feet beyond the thresholds. The runway also had 300-foot concrete blast pads extending beyond the thresholds at both ends. The runway slope was -0.6 percent, from north to south, with a drop in elevation of 38 feet over the 6,300 foot runway length. JAC utilizes two devices to assess runway friction values, including a Saab 9-5 SFT vehicle and Tapley decelerometer. The results of friction tests are subsequently relayed to the air traffic control tower.

Review of airport snow removal operations by a National Transportation Safety Board Survival Factors Specialist revealed that snow removal activities at JAC had been ongoing due to the snow and that “brooms and plows” were used. Review of Notices to Airman issued by JAC revealed that at 0630, runway 19 MU values were reported as 41, 37, 36 with patchy thin snow over patchy thin packed snow and ice on the runway surface. At 0920, MU values were reported as 40, 42, 40, with patchy thin snow over patchy thin packed snow and ice on the runway surface. Review of printouts from the Saab SFT revealed that at 0936, MU values for runway 19 were recorded as 34, 33, and 23.

The Federal Aviation Administration (FAA) Aeronautical Information Manual, Chapter 4, section 3, part 4-3-9, subpart B, states "The greek letter MU (pronounced "myew"), is used to designate a friction value representing runway surface conditions. " Subpart C states in part "…MU (friction) values range from 0 to 100 where zero is the lowest friction value and 100 is the maximum friction value obtainable. For frozen contaminants on runway surfaces, a MU value of 40 or less is the level when the aircraft braking performance starts to deteriorate and directional control begins to be less responsive. The lower the MU value, the less effective braking performance becomes and the more difficult directional control becomes. " Subpart G states in part "...No correlation has been established between MU values and the descriptive terms "good," "fair," "poor," and "nil" used in braking action reports."

Review of the company Flight Operations Manual (FOM) revealed that in section 2.4.10, Additional Requirements – Takeoff and/or Landing Operations, part 2, subpart B, states in part "… if current weather or runway surface conditions, the aircraft's status, or any other relevant factor, has worsened significantly from that used in landing distance planning (for release), and the worsened condition(s) would have a significant negative impact on the 'Actual Landing Distance' ...the Flightcrew shall calculate the 'Actual Landing Distance' for the current existing conditions, using AFM data. To this calculated 'Actual Landing Distance' is added a 15% safety margin. The 'actual landing distance' plus the 15% safety margin must allow for landing within the available length of the intended runway." In addition, part 4 states in part "...any 'braking action report' used to make a determination affecting landing of a NJA, Inc. aircraft must be from a similar aircraft. This would encompass turbojet powered aircraft of at least similar size to a Citation V up to and including Gulfstream IV/V or; a turboprop aircraft of at least similar size to a Beech/Raytheon King Air up to and including commuter-type turboprop powered airplanes."

Review of recorded weather data at JAC revealed a special weather observation report (SPECI) was recorded at 0920, reporting wind from 180 degrees at 11 knots, visibility one-half statute mile, light snow, blowing snow, broken ceiling at 500 feet, overcast cloud layer at 2,500 feet, temperature -7 degrees Celsius, dew point -9 degrees Celsius, and an altimeter setting of 29.60 inches of Mercury. At 0955, the recorded weather observation indicated wind from 200 degrees at 13 knots, visibility one-half statue mile, light snow, blowing snow, broken ceiling at 500 feet, overcast cloud layer at 1,400 feet, temperature -6 degrees Celsius, dew point of -9 degrees Celsius, and an altimeter setting of 29.61 inches of Mercury.

NTSB Probable Cause

The flight crew's inability to stop the airplane during landing roll on a snow- and ice-contaminated runway. Contributing to the runway overrun were the deteriorating runway conditions.