70 AUGUST 2018 ÇPlane&Pilot
Why do pilots continue lying into mountainsides
with the airplane fully under control? he term
controlled light into terrain (CFIT) puts an objec-
tive and rather cold label on a type of accident that has
deied prevention. For example, I was going through some
old Civil Aeronautics Board documents and noticed that
on March 1, 1938, a TWA DC-2 en route from San Francisco
to Winslow, Arizona, crashed into a mountain in Yosemite
National Park near Wawona, California. All nine on board
were killed. he DC-2 departed visually but it soon entered
instrument conditions, and the weather kept deteriorat-
ing. he pilot elected to divert to Fresno but apparently
became confused about his position in relation to the
Fresno Radio Range. he airplane’s wreckage was located
about three months later about 200 feet below the summit
of the mountain.
It’s not as if we don’t have better charts and moving maps
and VOR and GPS and RNAV and other technology that the
pilot of that DC-2 couldn’t imagine. Fast forward to April of
this year, and aviation seems to be still stuck where it was
80 years ago. April is when the NTSB released its report on a
Part 135 CFIT accident along with Safety Recommendations
which included a call for better training of Part 135 pilots
in CFIT accident avoidance.
It was on October 2, 2016, at about 11:57 a.m. that Ravn
Connect light 3153, operated by Hageland Aviation Services,
Inc., of Anchorage, Alaska, lew into steep mountainous
terrain about 10 miles northwest of the Togiak Airport
(PATG), Togiak, Alaska. he Part 135 light was operating
under VFR. here were two pilots and one passenger; all
were killed.
he airplane was a Cessna 208B Grand Caravan. he 1995
turboprop was powered by a Pratt & Whitney PT6A-114A
engine. he Cessna 208B could be conigured with two pilot
seats and as many as eight passenger seats depending on the
mission and whether it was for passengers, cargo or a mix.
he airplane could be lown by one pilot, but Hageland
often had a second-in-command on board.
he airplane had accumulated 20,562 hours total time,
and the next maintenance/inspection was due at 20,600
hours. It was being lown with its ADS-B system inoperative,and the repair had been deferred since ADS-B wasn’t
required by the airplane’s minimum equipment list.
he airplane had a Garmin GNS 430W and a Bendix/
King (Honeywell) KLN 89B for GPS navigation, a Garmin
GMX 200 multifunction display (MFD), a Bendix/King
(Honeywell) KGP 560 general aviation enhanced ground
proximity warning system (GA-EGPWS) that provided ter-
rain awareness and warning system (TAWS) capabilities,
and a MidContinent MD41-1200-series terrain awareness
annunciation control unit.
he GMX 200 MFD had a custom map function, which
used shades of green, brown and blue to depict terrain and
water. Traic information could also be displayed on the
custom map page. he terrain function would show the pilot
a terrain map related to what was around the airplane’s
position. Yellow depicted terrain that was within 1,000 feet
below the airplane’s altitude, and red depicted terrain 100
feet below and well above the airplane’s altitude. he MFD
relied on an internal terrain database.
he airplane met its requirement under Part 135 to be
equipped with an approved Terrain Awareness and Warning
System (TAWS) by having a Bendix/King (Honeywell) KGP
560 General Aviation Enhanced Ground Proximity Warning
System (GA-EGPWS).
he equipment used an internal GPS receiver and terrain
database to deine conlicts. It could check on what was
ahead of the airplane’s lateral and vertical paths to provide
alerts if a CFIT threat existed. If the airplane was more than
15 miles from an airport and it got within 700 feet of ground
level, an alert would go of. he system would provide an
alert if the airplane was within a minute of hitting terrain
ahead and more intense alerts when the airplane was about
30 seconds from terrain.
When using the custom map or most other functions
of the GMX 200, a terrain thumbnail would appear in
the upper left corner of the display. A white advisory lag
would appear when the airplane would be within 100 feet
of a terrain hazard within about 2 minutes of light in any
direction. he white terrain advisory lag would lash for
about 10 seconds then turn solid as long as the advisory
remained valid.
he Honeywell KGP 560 would produce voice messages
that could be routed to pilot headphones or the cockpit
speaker such as, “CAUTION TERRAIN (Pause) CAUTION
TERRAIN” and the more urgent “OBSTACLE, OBSTACLE,
PULL UP” or “TERRAIN, TERRAIN, PULL UP.”
Lights would appear on the annunciation control unit
on the top left side of the instrument panel. An amber light
meant caution; a red light indicated a terrain warning.
he terrain awareness annunciation control unit also
provided a terrain inhibit (TERR INHB) switch that put the
TAWS computer in standby mode. When the pilot pushed
the switch, a white TERR INHB light would come on and
remain on until the pilot pushed the switch again to again
allow the alerts.
At the time of the accident, Hageland employed about 120
pilots and operated 56 airplanes based at various airports
throughout Alaska. he company operated about 55,000CFIT
Controlled Flight Into Terrain
AFTER THE ACCIDENT
By Peter KatzPORTRAIT: LARA TOMLIN