Indication Was 300 Feet High

The altimeter on a medical helicopter that went down near Evansville, IN, last year was set incorrectly, according to an NTSB preliminary report. As a result, the flight crew aboard Air Evac 17 may have thought they were flying 300 feet higher than they actually were.

That was one finding in the NTSB factual report on the April 20, 2004 mishap that destroyed N137AE, a 13-year old Bell 206L-1 helo configured for medical operations.

The altimeter setting at EVV recorded 12 minutes after the accident was 29.77 inches of mercury. Inspection of the wreckage revealed the altimeter was set to 30.08 inches of mercury. This setting would have resulted in the altimeter indicating that the altitude was approximately 310 feet higher then the actual altitude of the helicopter. It should be noted that the helicopter was flown for 0.4 hours earlier on the day of the accident. The aircraft logs indicate that the flight previous of that was on April 19th at 1848 when the helicopter was flown to Poland, Indiana. The closest weather reporting station to Poland is located at Terre Haute, Indiana. The altimeter setting recorded at Terre Haute at 1853 on April 19th was 30.08 inches of mercury. In addition, the altimeter setting recorded at LWV, the weather reporting station closest to the departure airport, at 1853 was 30.09 inches of mercury.

There were also indications of an occasional problem with the DH bug in the radar altimeter. The NTSB report said, in part:

During inspection of the wreckage the DH bug was found to be set at about 75 feet. In January 2001, the accident pilot took a written test on which one of the questions was "The radar altimeter shall be set to." The pilot answered that is should be set at 300 feet during the day and 500 feet at night. The pilot scored 100% on the test. Following the accident, the Vice President of Operations for Air Evac sent an email to all company pilots reiterating the company policy for setting the radar altimeter to a minimum altitude of 300 feet for day visual flight rules (VFR) operations and 450 - 500 feet for night VFR operations. On January 10, 2005, the company operations manual was revised to include these procedures.

The report indicated the aircraft's rotors dug into the rising terrain immediately as the accident began to unfold.

The wreckage path was 187 feet in length along a magnetic heading of 233 degrees on up-sloping terrain. The initial ground scars consisted of two parallel scars, which were approximately 3 inches wide and spaced about 7 feet apart. In the middle of these scars was a wider ground scar which contained the cutter from the wire strike protection system and the search light assembly. The cutter was buried in the ground. There was a strong smell of fuel present in this area. Just beyond this scar was a section of the forward crosstube.

Approximately 19 feet to the right of the center ground scar were three parallel slash marks in the terrain. These marks ranged from 14 feet 7 inches to 3 feet 3 inches in length. The main wreckage was approximately 93 feet from the last of these slash marks.

The helicopter came to rest on its right side. The fuselage was fractured just forward of the tail boom attach point. The lower forward portion of the fuselage and the nose sustained substantial impact damage. Both the forward and aft fuel cells were ruptured. The center post was intact and attached at the upper cockpit area. The lower portion of the center post was detached from the surrounding structure. The instrument panel was separated from the surrounding structure. The grass located behind the engine exhaust was burned. A melted plastic soda bottle that was located on the ground behind the exhaust.

The pilot, 42-year old Richard LaRock, was pinned in the wreckage for a time.

The emergency medical technicians (EMT) who treated the pilot at the accident site reported that the pilot stated "Boy I screwed up." An EMT asked him what happened and the pilot reported, "I started making my turn and we started tumbling."

The passenger, a 63-year old patient, was killed in the mishap.

FMI: www.ntsb.gov/ntsb/brief2.asp?ev_id=20040426X00513&ntsbno=CHI04FA107&akey=1