Clipper
Climax
George Terhune
"I was the first first Pan
Am employee on the site, along with two US Army personnel from the
Jakarta embassy, an Indonesian from their Dept of Aviation, and some
Indonesian Army personnel, for a preliminary look at the wreckage about
a week after the accident. At that time we determined the general
layout, and that the Flight Data Recorder (FDR) and Cockpit Voice
Recorder (CVR) were no longer attached to the structure where they
should have been, and were probably buried pretty deep in a pile of
wreckage at the bottom of a gully.
I took part in the official accident investigation on site, along with a
Pan Am maintenance chief, some Indonesians from the Dept of Aviation,
and of course a good many Indonesian Army personnel as escorts. I
was one of three Pan Am people, along with a half dozen Balinese workers
and an Army
escort, who returned to the site almost three months later, when we took
about 10 days to dig out the recorders. I later obtained readouts of the
recorders and did my own plot and analysis of the flight path and
cockpit conversations at each point in the last part of the flight.
Finally I attended the hearing in Jakarta the following March (I
believe), where I first heard most of what eventually appeared in the
accident report (and a > lot more).
The particular parts of the
Report I find most objectionable are in the excerpts below [between the
dotted lines]. My comments:
1. Nothing in the recordings or the crew’s actions can support the
statement that they "…intended to make a right turn WITHIN 25 MILES"
of the beacon. The mention of "25 miles" was only as part of the
pre-approach briefing, where they noted the Minimum Safe Altitude of [I
believe] 12,000ft within 25 miles, which was due to the high terrain on
the NE part of Bali. In fact, they had a clearance to a lower altitude
[because the minimum altitude for their course was lower], but they did
not descent below 12,000ft until they thought they had a valid overhead
"needle swing." The "25 mile" statement showed an abundance of
appropriate caution, not any intention to turn early.
2. There is no evidence that "… the crew in an attempt to expedite
their approach into Bali Airport, elected to execute an early right hand
turn." The turn was no doubt a mistake, but it was in no way an
"election." This erroneous conclusion by the accident board was probably
based in part on an error in the flight path map they were given
by the US NTSB. The NTSB specialist missed a heading change that clearly
showed on the FDR trace, so
the NTSB map showed a large zig-zag turn, which did not look like the
proper approach procedure. I called this error to the attention of the
NTSB representative at the hearing, but he would not correct it. I
spoke up about this issue on my own at the hearing, but the board
ignored my input, except
[as I remember it] they did move their statement about "intention" from
the "Probable Cause" to a "Finding."
3. There is no evidence that "…the pilot-in-command was not very
familiar with the Indonesian Aeronautical Information Publication,
specifically related to local procedures at Bali International Airport."
The crew properly briefed themselves on the approach, and conducted it
correctly, except of course for being in the wrong place. That was a
fatal mistake, but it did not arise from intention or lack of
familiarity with proper procedure.
4. The pilot did not "assume" he was "nearing" the beacon. He THOUGHT he
was OVER the beacon. The whole thing was an experience I’m very glad I
had, but have no wish ever to repeat.
————-
It was further disclosed that the pilot intended to make a right hand
turn within 25 miles from the beacon for a track out on 261 degrees,
descending
to 1 500 ft followed by a procedure turn over the water for final
approach on Runway 09 which was the runway in rise given by Bali
Control.
The Board is of the opinion that the crew in an attempt to expedite
their approach into Bali Airport, elected to execute an early right hand
turn for
track out on 263 degrees. By using this type of approach they were
prevented from knowing their tract position. Such an early turn would
necessitate the pilot’s obtaining an early indication on the ADF that
the was nearing the NDB. Evidently the right hand turn was made at the
time when only one of the ADF needles swung. According to the
reconstruction of the flight path, based on information obtained from
the flight recorder, it is evident that the
right hand turn was made at a position approximately 30 NM North of the
beacon.
The flight crew was properly licensed and experienced to carry out the
flight. However, from the available data, the Board was led to believe
that the pilot-in-command was not very familiar with the Indonesian
Aeronautical Information Publication, specifically related to local
procedures at Bali International Airport.
At this point the pilot initiated a let-down procedure by making a right
hand turn for track out on 263 degrees, assuming that he was nearing the
NDB.
b) Cause or Probable cause(s)
The Board determined that the probable cause or this accident was the
premature execution of a right hand turn to join the 263 degrees
outbound
track which was based on the indication given by only one of the ADFs
while the other one was still in steady condition."
> ———–
>George Terhune
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