What's that frequency?

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AOPA Air Safety Foundation In the early morning hours of December 20, 2000, a Hawker HS-125 business jet was substantially damaged when it landed in snow next to the runway at Jackson Hole Airport in Jackson, Wyoming. Fortunately, neither the two pilots nor the two passengers were injured.

The airplane departed Austin, Texas, on an IFR flight plan 3 hours and 20 minutes prior to the accident. The most recent weather report for Jackson Hole indicated a direct right crosswind, gusting from 10 knots to 14 kt. Visibility was reported 5 miles with few clouds at 100 feet, scattered clouds at 1,000 feet, and overcast layer at 1,600 feet. The temperature was 25 degrees Fahrenheit.

As the flight neared Jackson Hole around 1 a.m., Salt Lake City Center cleared the flight for the full ILS approach to Runway 18. They were cleared to change frequencies to the common traffic advisory frequency 118.07.

The tower at Jackson Hole closes at 10 p.m. local time during the winter months. Because of the airport's location in a national park, the runway lights are off after the tower closes. They can be activated (pilot-controlled lighting) on the CTAF frequency.

Six months earlier, the pilot-controlled lighting still operated on the unicom frequency of 122.8. New charts had recently been issued that depicted a new frequency for lighting activation of 118.07. Two Jackson Hole Airport ILS Runway 18 approach charts were found in the airplane. One was out of date and the other was current and showed the separate PCL frequency.

According to the captain, when they were approximately 5 nautical miles from the airport and descending through about 2,400 agl, the copilot reported that he could see the ground. The captain said that the airport was in sight, the PAPI lights were visible along the left side of the runway, and the runway was in sight. He completed all of the landing checks, and the airplane was centered on the ILS localizer and glideslope.

The runway lights were not illuminated as the captain continued below approach minimums. While in the landing flare, he reported that strong crosswinds and blowing snow created a "white out" weather condition. The airplane touched down to the left of the runway and came to rest between the parallel taxiway and the runway in approximately two feet of snow.

Analysis of the cockpit voice recorder revealed that the captain was heard asking the copilot for the frequency of the pilot-controlled lighting. The copilot responded, "It'd be 122.8 if it's not on."

During the next few minutes, the copilot transmitted four times on 122.8 with eight to five clicks with his mic key each time. Just prior to touchdown, the captain asked, "Got any runway lights?" The copilot responded, "Says activate on 122.8, and that's what I'm on."

No mention was made in the accident report of an approach briefing occurring between the two pilots. During such a briefing, the two pilots might have uncovered the differing charts that each one had.

A highly experienced corporate flight crew might consider night approaches in IMC a routine event, but it's easy to see how quickly things can go wrong when proper procedures are not followed. 14 CFR FAR 91.175 is quite clear on the items that must be in sight to continue flight below decision height or minimum descent altitude while conducting an instrument approach. The missing runway lights were an unheeded clue.

Pilots who conduct the majority of their flying out of towered airports may need a refresher on procedures at nontowered airports. Check out The AOPA Air Safety Institute's Safety Advisor, Operations at Nontowered Airports , to make sure you're up to speed on after-hours arrivals and nontowered airport operations.


Accident reports can be found in ASI's accident database.