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.