Aviation Accident Summaries

Aviation Accident Summary FTW99LA012

EAGLE PASS, TX, USA

Aircraft #1

N19MH

Cessna 421C

Analysis

During takeoff climb, the twin-engine airplane encountered a strong downdraft and impacted trees and terrain. The pilot reported that while taxiing to the runway, he scanned the sky with the monochrome weather radar, which was set at the 40-mile range. 'No weather was shown behind the runway and a cell was shown 15 miles from the runway.' The takeoff roll was 'uneventful,' and the airplane was rotated at 95 knots. Climb out was accomplished at 110 knots, the engines were at maximum power, the propellers at maximum RPM, and the manifold pressure was indicating maximum. A 10-degree turn towards the Cotulla VOR was being made when at 1,500 feet msl, a sharp descent was felt with the VSI indicating an 800 ft/min rate of descent. The wings were leveled and the airspeed was slowed to 85 knots. 'The rate of descent slowed to 400 ft/min and then finally to 300 ft/min until impact...' The airplane was destroyed by fire that erupted on impact. A review of doppler weather radar images showed thunderstorms in the vicinity of the airport.

Factual Information

On October 18, 1998, at 0600 central daylight time, a Cessna 421C twin-engine airplane, N19MH, registered to and operated by Critical Air Medicine of San Diego, California, impacted terrain during takeoff climb from the Maverick County Memorial International Airport near Eagle Pass, Texas. The airline transport pilot, two flight nurses, the patient, and one passenger sustained minor injuries. Visual meteorological conditions prevailed, and a company VFR flight plan was filed for the 14 Code of Federal Regulations Part 135 air medical flight. The dark night flight was originating at the time of the accident, with San Antonio as its destination. The pilot reported to the NTSB investigator-in-charge during an interview and in a written statement that while taxiing to runway 12, he scanned the sky with the monochrome weather radar, which was set at the 40-mile range. "No weather was shown behind the runway and a cell was shown 15 miles from the runway. The takeoff roll was uneventful, the runway was wet, but no hydroplaning was encountered." The airplane was rotated at 95 knots, and the landing gear was retracted after reaching a positive rate of climb. Climb out was accomplished at 110 knots, and the "engines were at maximum power, propellers RPM maximum, and maximum manifold pressure. A 10-degree turn towards the Cotulla VOR was being made, when at 1,500 feet msl, a sharp descent was felt with the VSI indicating 800 ft/min rate of descent." The wings were leveled and the airspeed was slowed to 80 knots, then increased to 85 knots, where it stayed for the remainder of the flight. "The rate of descent was slowed to 400 ft/min and finally to 300 ft/min before impact... The tail impacted first and the nose was kept up until control was no longer possible. The airplane stopped and fire enveloped the airplane very quickly outside and inside." A flight nurse reported that during takeoff, the aircraft lifted off the runway and began to ascend. The ascent was smooth and there were "no different sounds from either engine." While attending to the patient, he heard a loud metal bang and had a falling sensation that lasted 1-2 seconds. He then saw a bright yellow flash to the right side of the airplane, proceeded by another yellow flash to the left side of the airplane. He felt the airplane still in forward motion, but with a "heavy turbulence" feeling and a noise that sounded like a "machine gun." After the aircraft came to a stop, the flight crew, patient and passenger exited the burning airplane. The fire destroyed the airplane. According to FAA records, the pilot telephoned the San Angelo AFSS twice the evening before the flight and was provided with a preflight weather briefing each time. At 0429, the pilot telephoned the San Angelo AFSS to file an IFR flight plan to San Antonio and was provided an update on weather. A review of doppler weather radar site images from the Del Rio, Texas (KDFX) WSR-88D radar at 0551, 0557, and 0603 on October 18, 1999, showed thunderstorms in the vicinity of the Eagle Pass airport.

Probable Cause and Findings

A downdraft, which exceeded the aircraft's climb performance. A factor was the thunderstorms in the vicinity of the airport.

 

Source: NTSB Aviation Accident Database

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