Safety Publications/Articles

Air Safety Institute Safety Spotlight

Boxed in

Early in training, we are taught to always have an "out," a failsafe option that ensures a safe outcome. On December 9, 2004, the pilot of a Piper Saratoga neglected that principle, boxing himself between two bad choices that ultimately led to a descent below the minimum descent altitude (MDA) for the Runway 33 GPS approach at Glenwood Municipal Airport in Glenwood, Minnesota. Both the pilot and his passenger were killed.

On the morning of the accident, the pilot called flight service to file three IFR flight plans. The first was from Florida to Georgia, the second from Georgia to Illinois, and the last from Illinois to Glenwood. He received a briefing that covered the first two legs of the flight but declined information related to the third leg. There was no record of any additional information provided to the pilot from any flight service station along the route of flight.

At 4:37 p.m., as the pilot approached Glenwood, Minneapolis Center instructed him to descend and maintain 6,000 feet; then, five minutes later, to 4,000 feet. The pilot asked to stay at "6,000 feet to stay out of the clouds here [until] the last minute [due to] possible icing." ATC agreed and issued a clearance to descend to 4,000 at the pilot's discretion.

Shortly thereafter, the pilot reported accumulating a "fair amount" of rime and mixed ice at 6,000 feet and requested a climb to 7,000 feet. He characterized the icing intensity as "light" and said that the cloud tops were at 6,200 feet.

The pilot was given vectors to the Runway 33 GPS approach course, and radar recorded the aircraft intercepting the course at an altitude of 6,000 feet at 5:03 p.m. ATC then cleared the flight for the approach, and the pilot reported being established on the approach. A frequency change was approved, and there was no further radio contact.

The MDA for the approach was 372 feet agl. A witness to the accident said she heard a low-flying airplane, spotted its lights, and then saw it dive and crash. It was dark at the time, with mist and fog. The Glenwood AWOS reported a ceiling of 200 feet agl overcast shortly before the accident--almost 200 feet below the MDA.

The NTSB determined the cause of this accident to be the pilot's failure to execute a missed approach and maintain sufficient altitude and clearance from terrain. Contributing factors include the pilot's failure to obtain a weather briefing, icing, and ceilings below the MDA for the approach. At the time of the accident, the instrument-rated private pilot had accumulated more than 700 hours of total time, with 85 hours of instrument experience.

A descent through nearly 5,000 feet of clouds with known icing conditions could result in a significant amount of ice accumulation, and the accident aircraft was not equipped for flight into known icing. The farther the pilot continued on this flight, the fewer choices he had. By proceeding with the approach into Glenwood he was left with two choices--fly the missed approach procedure and pick up more ice or go below minimums and try to land the aircraft. He chose to attempt a landing. If he had diverted before executing the approach, the results likely would have been dramatically different.

For more information about icing and its dangers, visit the AOPA Air Safety Foundation's Safety Hot Spot on aircraft icing, where you will find many resources related to in-flight icing and how to avoid it.

Kristen Hummel manages the GA accident database for the AOPA Air Safety Foundation. She holds a commercial pilot certificate with multiengine and instrument ratings.

By Kristen Hummel

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