Aviation Accident Summaries

Aviation Accident Summary SEA96LA056

CASHMERE, WA, USA

Aircraft #1

N52264

Cessna 172P

Analysis

The pilot diverted from his original destination due to weather conditions at the destination airport. The runway at the selected alternate was 1,800 feet long with a 1.3 percent down grade from west to east. Winds at the time were calm. The pilot did not follow the landing procedure specified in an onboard airport guide, directing landings uphill to the west in calm winds; instead, he initiated a landing downhill to the east. The airplane's pilot operating handbook (POH) indicated a 530-foot short-field landing ground roll on a level field under conditions of gross weight, pressure, and temperature approximating those of the accident flight; total distance to land after clearing a 50 foot obstacle was about 1265 feet. Subsequently, the airplane ran off the east end of the runway, encountered snow, and nosed over despite heavy braking attempts by the pilot. During a postaccident examination, the flaps were found in an extended position. The POH stated that during a short-field landing, flaps should be retracted during the landing roll for maximum braking effectiveness.

Factual Information

On February 16, 1996, approximately 1045 Pacific standard time, a Cessna 172P, N52264, operated by AeroFlight Executive Services, Inc. of Seattle, Washington, a 14 CFR 135 on-demand air taxi certificate holder, was substantially damaged when it overran the landing surface and nosed over at Cashmere-Dryden Airport, Cashmere, Washington. There were no injuries to the commercial pilot or 3 passengers on board. The 14 CFR 135 on-demand air taxi flight had originated at Boeing Field in Seattle and, according to FAA air traffic service records, had originally planned to proceed to Wenatchee, Washington. Visual meteorological conditions existed at the accident site and a visual flight rules (VFR) flight plan had been filed. FAA air traffic service records indicated that the pilot initially called the Seattle automated flight service station (AFSS) at 0722 on the morning of the accident and requested a standard briefing for a flight to Wenatchee. The briefing transcript indicated that the briefer told the pilot that Wenatchee was reporting instrument conditions, that VFR flight was not recommended at that time, and that the pilot replied that "I gotta have [VFR] to go" and that he would "keep getting updates" on the weather. The pilot called again for updates at 0735, 0758, 0803, 0900, and 0905, according to briefing transcripts. The 0905 briefing transcript indicated that the pilot was informed that "any time now...it should...open up to two hundred scattered three miles in fog", and that he also received a pilot report which indicated "thin patchy fog over [Wenatchee]" which was "not very thick." The briefer also told the pilot that there was no wind at Wenatchee at the time but that "as soon as it starts moving it'll clear out." The flight subsequently departed Boeing Field at 0945. Weather information in the air traffic service records indicated that the 0854 Wenatchee observation consisted of a partial obscuration with 100-foot measured overcast ceiling and visibility less than 1/4 mile; however, the Wenatchee terminal forecast was for scattered clouds at 200 feet with visibility 3 miles in fog by 0900, improving to scattered clouds at 25,000 feet by 1000. The pilot's written statement of the accident stated: "...Arriving in the Wenatchee area, [the airport] was reporting IFR [instrument flight rules] conditions. At this time I observed that Cashmere had clear skies and unrestricted visibility. I circled and announced my intentions over the radio. While circling I noticed the absence of numbers for runway 25, and that the winds were calm, then overflew runway 7 twice. On the third pass I touched down approximately 1/4 of the way down. [NOTE: The runway length at Cashmere-Dryden is 1,800 feet.] I applied the brakes but did not appear to be slowing down. I then made the decision that a go-around was not the best alternative and heavily applied the brakes. The plane went off the east end of the runway, hitting heavy snow and flipping the plane over...." At the accident scene, skid marks were noted on the eastern 720 feet of the runway, continuing off the end of the runway. It was also noted that the flaps on the accident aircraft were down. Individuals who were at the airport at the time of the accident stated that the runway was dry at the time. The 1054 Wenatchee automated weather observation was: sky partially obscured, measured ceiling 100 feet overcast, visibility less than 1/4 mile, temperature 31 degrees F, dewpoint 30 degrees F, wind calm, and altimeter setting 30.14 inches Hg. The lowest IFR approach minimums for Wenatchee contained in U.S. Government terminal instrument approach procedures are for circling VOR or Global Positioning System (GPS) approaches with Category A visibility requirements of 1 1/4 statute miles. The Western States Flight Guide (Airguide Publications) indicates that the runway at Cashmere-Dryden slopes uphill from east to west with a 1.3 percent grade. AeroFlight furnished a copy of the Cashmere-Dryden flight guide entry to investigators, and stated that its pilots have this guide aboard the aircraft on 14 CFR 135 air taxi flights. The guide instructs pilots landing at Cashmere-Dryden to land uphill on runway 25 when winds are 5 knots or less. The Pilot's Guide to Washington Airports (Washington State Department of Transportation, 1994) contains an overhead photograph of the airport which shows conspicuous runway numbers at both ends. The author of the state airport guide stated to the NTSB investigator that the photo was taken in approximately the summer of 1993. The Cessna 172P pilot's operating handbook (POH) states the following regarding short field landing procedures: "...For maximum braking effectiveness, retract the flaps, hold the control wheel full back, and apply maximum brake pressure without sliding the tires." The POH gives the short field landing distance as a 530-foot ground roll, or 1,265 feet total to clear a 50-foot obstacle, under the following conditions: flaps 30 degrees, power off, maximum braking, paved level dry runway, zero wind, 2,400 pounds gross weight, pressure altitude 1,000 feet, temperature 0 degrees C (32 degrees F), and short field technique as specified in section 4 of the POH (which includes the instructions regarding braking effectiveness quoted above.) Cashmere-Dryden is 853 feet above sea level. The temperature at the field at the time of the accident, as reported on the operator's accident report, was 31 degrees F.

Probable Cause and Findings

the pilot's selection of the wrong runway for landing, by not observing a procedure to land uphill during calm wind conditions, and his subsequent failure to retract the flaps during landing roll, as recommended by the airplane's short-field landing procedure. The downhill slope of the landing runway was a related factor.

 

Source: NTSB Aviation Accident Database

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