Pan American World Airways, Boeing 707-321C, accident at Tinga-Tinga, Bali, Indonesia, on 22 April 1974.
dated 20 March 1975 released by the Ministry of Transport, Communications and
by Harro Ranter
Aircraft Accident Digest (ICAO Circular 132-AN/93) page 126-133.
History of the flight
PA-812 was allocated flight level 330 from Hong Kong until BTT and thence
proceeded at flight level 350 until Denpasar. The flight proceeded normally and
position reports while in Indonesian UIR were carried out through Jakarta Radio
on frequency 5673 kHz.
1428 PA-812 was cleared by Jakarta area Control Centre to descend to flight
level 280. PA-812 established its first contact with Bali Tower at 1506 through
Tower Frequency 118.1 MHz and was instructed by Tower to contact Bali control on
frequency 128.3 kHz.
1508 PA-812 informed Bali Control of revised ETA 1527. A clearance to descend to
flight level 100 was given by Bali Control and at 1509 a request was made by the
aircraft for active runway. Runway in use 09 was passed on by Bali Control to
descent to flight level 120, after observing that one of the ADF needles swung,
at 1519 PA-812 reported over the station turning outbound and was subsequently)
instructed to contact Bali Tower. Twenty-five seconds later PA-81Z established
contact with Bali Tower informing outbound procedure, followed by a request for
was then given to descend to 2 500 ft and PA-812 was instructed to report
reaching 2 500. At 1523 the aircraft reported reaching Z 500 it and Bali Tower
gave instructions to continue approach and to report when runway was in sight.
Acknowledgement was made by PA-812 by saying "Check inbound". At 1526
the pilot-in-command requested the visibility by calling "Hey – Tower, what
is your visibility out there now?"
according to the transcription of Air Traffic Control voice recorder this
message was never received by Bali Tower. Apparently this was the last message
transmitted by the aircraft. Bali Tower kept trying to contact the aircraft by
calling "Clipper eight one two, Bali Tower" and "Clipper eight
one two, Bali Tower, how do you read" several times. However, no answer was
received from the aircraft. it was subsequently found that the aircraft hit a
mountain approximately 37 NM North-West of Ngurah Rai Airport.
Injuries to persons
OthersFatal1196-Non-Fatal—None—No identification and toxicological
examination of the victims could be made. The number of victims stated above was
based on the passenger manifest and the crew list.
Damage to aircraft
the time of the accident he had flown a total of 18 247 hours including 7 192
hours in Boeing 707/720 aircraft. His last FAA medical examination took place on
13 December 1973, with a limitation to wear glasses while flying an aircraft. He
had flown 33 hours during the last 30 days and 3:40 hours during the 24 hours
prior to the accident. His last proficiency check was carried out on 24 October
1973. His last entry to Denpasar was on 16 May 1973 on flight PA-811 from Sydney
to Hong Kong via Denpasar.
first officer, aged 40, held a valid ATPL endorsed for Boeing 707/720. At the
time of the accident he had flown a total of 6 312 hours including 4 776 hours
in Boeing 707/720 aircraft. His last FAA medical examination took place on 5
December 1973 and there were no limitations imposed. He had flown 40 hours
during the last 30 days and 3:40 hours during the 24 hours prior to the
accident. His last proficiency check was carried out on 7 December 1973. His
last entry to Denpasar was on 16 July 1973 on flight PA-812 from Hong Kong to
Sydney via Denpasar.
second officer, aged 38, held a valid Commercial pilot’s license and a current
instrument rating. At the time of the accident he had flown a total of 4 255
hours including 3 964 hours in Boeing 707/720 aircraft. His last FAA medical
examination took place on 8 March 1974 with no limitations imposed. He had flown
74:27 hours during the last 30 days and 3:40 hours during the 24 hours preceding
the accident. His last Proficiency check was carried out on 15 February 1974.
His last entry to Denpasar was On 27 February 1974 on flight PA-812 from Sydney
to Hong Kong via Denpasar.
flight engineer, aged 48, held a valid flight engineer’s license. At the time of
the accident he had flown a total of 14 375 hours including 7 175 hours in
Boeing 707/720 aircraft. His last FAA medical examination took place on 5
November 1973 with a limitation to wear glasses while on duty in the aircraft.
He had flown 26 hours during the last 30 days and 3:40 hours during the 24 hours
preceding the accident. His last proficiency check ride was carried out on 21
March 1974. His last entry to Denpasar was on 17 December 1973 on flight PA-812
from Hong Kong to Sydney via Denpasar. The second flight engineer, aged 43, held
a valid flight engineer’s license. At the time of the accident he had flown a
total of 7 986 hours including 4 965 hours in Boeing 707/720 aircraft. His last
FAA medical examination took place on 6 August 1973 with a limitation to wear
glasses while on duty in the aircraft. He had flown 32 hours during the last 30
days and 3:40 hours during the 24 hours prior to the accident. His last
proficiency check ride was carried out on 8 January 1974. His last entry to
Denpasar was on 16 January 1974 on flight P4-811 from Sydney to Hong Kong via
the aircraft maintenance log it appeared that all actions to correct
discrepancies had been taken and properly accomplished. All Airworthiness
Directives, Engineering Authorizations and Quality Control Authorizations had
been complied with. The last "A" check was accomplished at a ship time
of 27 943 hours on 22 April 1974 at Hong Kong Airport, whereas the last
"B" check was accomplished on 13 April 1974 at’ total aircraft time of
27 838 hours.
power plants were four Pratt and Whitney JT3D model 3 BAB engines.
serial number 668583 was installed on N 446 PA on 9 April 1973 in the number one
position. At the time of the last recorded maintenance accomplished at the
termination of flight number 811/20 at Hong Kong Airport, the total engine time
was 15 133 hours and the time since last overhaul was 15 133 hours, the total
engine cycles were 5 590. The last combustion area inspection at TSO (time since
last overhaul) 11 732, was done at 3 Periodic/Shop Visit on 24 July 1972. The
test cell run was made on 15 September 1972.
serial number —— was installed on N 446 PA on ——————- in the*
number two position. At the time of the last recorded maintenance at the
termination of flight number 811/20 at Hong Kong Airport, the total engine time
was 18;75 hours and the time since last overhaul was 16 248 hours. The total
engine cycles were 6 815. The last combustion area inspection at TSO 15 320, was
done on a Periodic/Shop Visit on 31 July 1973. The test cell run was made on 19
serial number 644755 was installed on N 446 PA on 4 March 1974 in the number
three position. At the time of the Last recorded maintenance at the termination
of flight number 811/20 at Hong Kong Airport, the total engine time was 28 409
hours and the time since last overhaul was 10 596 hours. The total engine cycles
were 9 388. The last combustion area inspection at TSO 9 723, was done on a
Periodic/Shop Visit on 19 July 1973. The test cell run was made on 13 August
serial number 667727 was installed on N 446 PA on 18 April 1974 in the number
four position. At the time of the last recorded maintenance at the termination
of flight number 811/20 at Hong Kong Airport the total engine time was 20 049
hours. The total engine cycles were 6 040. The last combustion area inspection
at TSO 19 999, was done on a Periodic/Shop Visit on 5 July 1973. The test cell
run was made on 2 April 1974.
to the transcript of the Cockpit Voice Recorder, at 1519:42 Bali Tower informed
PA-812 that the surface weather at Bali Airport was as follows: wind 110/5 kt,
altimeter setting 29.87 in Hg.
to the meteorological report for take-off and landing made by the meteorological
officer at Bali Airport at 1500, the surface weather at Bali Airport was as
and time: 22 April 1974, 1500.Surface wind : 110/5 kt.Horizontal visibility : 8
NM.Cloud : 1 Oktas Cu 2 000 ft.Altimeter setting : 1 011.6 mb or 29.87 in
Hg.Pressure at aerodrome elevation: 1 011.1 mb or 29.86 in Hg.According to
eyewitness observations, the weather at the accident site was clear (cloudless),
the stars were bright and it was moonless.
Aid to Navigation
was finally established at 1506 with Bali Tower on 118.1 MHz and PA-812 was then
instructed to contact Bali Control on 128.3 Mhz. Subsequently the communication
between the aircraft and the ground was normal. No message indicating evidence
of either distress or emergency was received by Bali Air Traffic Control prior
to the accident.
Aerodrome and around facilities
is equipped with runway lights, threshold lights, taxiway lights, VASI, rotating
light beacon and landing tee. The rotating light beacon was unserviceable during
the time of the accident.
failure of electric power supply was experienced at the time of the accident.
Flight data recorder
flight data recorder was a LAS 169-C model having serial number 443. Examination
of the cassette showed minor mechanical damage. The foil recording medium was
removed from the cassette and found to have several mechanical tears and
deformation due to impact, apparently as a result of the accident. No evidence
of fire or heat damage was noted on the cassette or foil. It was noted that 311
parameter traces had been recorded at the time of the accident. Basic reference
measurements disclosed that the recorder had been operating in a manner
consistent with the current calibration with no evidence of recorder malfunction
or recording abnormalities. The read-out done by the NTSB laboratory was started
,it a point when the aircraft was at cruising altitude of 34 000 ft pressure
altitude and covered the last 39 minutes and 30 seconds of recorder operations.
The read-out covers a period of several seconds after impact, however, the tract
point of impact was not definitely established.
Cockpit voice recorder
cockpit voice recorder was also recovered and sent to the U.S. National
Transportation Safety Board for evaluation. It yielded a good readable tape and
a transcription- was made of the past thirty minutes of the flight. The NTSB’s
comprehensive read out indicated that evaluation started at cockpit voice
recorder time of 1456:14 and the read-out indicated that tile impact occurred at
1526:42.9. A review of the tape revealed that the cockpit voice recorder been
operating satisfactorily up to the time of the accident.
aircraft disintegrated after its final impact and the wreckage was scattered
within a radius of 50 m from the point of impact.
investigation at the crash site revealed that no fire broke out prior to the
burnt area at the place of aircraft impact, which showed signs of fire from
below towards the top of the trees, led to the belief that fire only occurred
after the aircraft hit the ground. Further examination of the wreckage revealed
that the main and nose landing gears were in down and locked positions. It was
found that the right- hand wing tip struck several trees first at approximately
50 m from the impact point and then the aircraft entered a gap approximately 100
ft wide between two large trees. The right hand wing was sheared off at its root
and broken into four parts. The left hand wing struck a ridge and was broken
into three separate parts. It was observed that a burnt area was shown close to
the main impact area, which indicated that fire broke out immediately after
impact. From the distribution of the wreckage no evidence of in-flight explosion
could be found.
Analysis and Conclusions
cockpit voice recorder further disclosed that the pilot-in-command had
encountered no difficulty with the procedures to land at Bali Airport, in which
it was mentioned to maintain at 12 000 ft until the beacon and then to execute
the full ADF let-down procedure. The cockpit voice recorder also disclosed that
the pilots were aware Of the existence of a 7 000 ft mountain 26 miles North of
Bali Airport, another 10 000 ft mountain north-north-fast of the airport and
that flight level 120 would clear them from the mountains mentioned above. From
the conversation amongst flight crew members it was further disclosed that the
estimated time of arrival was 1527, which was subsequently Passed to Bali
Control. 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.
recorded by the cockpit voice recorder at approximately 1518 the crew observed
that ADF number one was swinging while ADF number two remained steady, i few
seconds later at 1519 PA-812 reported to Bali Control that he was over the
station turning outbound descending to flight level 120. This was acknowledged
by Bali Control and PA-812 was then instructed to change over to Bali Tower.
Having established contact with Bali Tower, PA-812 reported making outbound
procedure flight level 110 and requested lower altitude. Clearance was given by
Bali Tower to descend to 2 500 ft, with instructions to report at that height.
At 1523 PA-812 reported reaching 2 500 ft.
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.
several attempts were made to regain proper indication on the ADFs after the
turn, the Board believes that this would not have been possible since the
aircraft would be shielded by the mountain range. However, the approach was
continued as planned resulting in a collision with high ground.
flight data recorder and cockpit voice recorder read-outs revealed no evidence
of any aircraft abnormality during any part of the flight prior to the accident.
aircraft was properly certificated and airworthy at the time of accident.
was no sign of explosion prior to impact.
was no evidence of any break up in flight.
was also no sign that may have indicated a possible fire prior to the impact
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
weight and centre of gravity of the aircraft were within allowable limits at the
time of the accident.
of the ADFs swung while the other remained steady when the aircraft was still
about 30 NM North of the beacon.
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.
evidence was found regarding the possibility of interference to the ADF induced
by radio broadcasting station.
Board has not succeeded in determining the cause of the needle swing of one of
the ADFs. It may have been caused by either external or internal interference.
Cause or Probable cause(s)
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.
Board submits the following recommendations:
should encourage pilots towards a more thorough knowledge of the aeronautical
information published in the Operations Manual for a certain airport, to avoid
the possibility of divided attention during the critical stages of the approach.
observation by the Operator’s Flight Safety Officer to help them avoid accidents
due to human error during a possible accident prone stage in the course of their
career would be welcomed by even highly experienced pilots.
it has no bearing on this particular accident, the installation of a DME in
addition to the existing VOR at Denpasar would be of great help to aircraft.
? 1996-98 Harro Ranter/Aviation Safety Web Pages; Updated 16 May 1998
2001 PanAmAir.org ? Email PanAmAir.org