Kecelakaan Sukhoi Super Jet 100 di
Gunung Salak pada tanggal 9 Mei 2012 itu sangat menyedihkan dan terasa sangat
memukul dunia penerbangan kita, bagaimana tidak jumlah korban yang lumayan
banyak karena gara gara banyak pihak tidak melakukan pekerjaannya dengan BAIK
dan BENAR (Penerbang, ATC, Radar, Briefing office dll.).
Tanpa menyalahkan siapapun berikut
saran saran perbaikan kepada banyak pihak terkait. Seperti Penerbang seharusnya
selalu mengikuti aturan terbang yang ada yaitu dengan mengikuti aturan
Instrument Flight Rule(IFR) standard approach navigasi VOR kalau pesawat mau
mendarat memakai runway 06 Halim.
Kalau mengikuti aturan IFR
(Instrument Flight Rule), pesawat seharusnya baru boleh menurunkan ketinggian di atas VOR Halim
(dekat runway Halim Perdana Kusumah). Kalau pesawat menurunkan ketinggian di
atas runway Halim PK pasti dijamin akan aman dan tidak akan ada kecelakaan.
Tetapi kalau pesawat menurunkan ketinggian tidak mengikuti aturan IFR, apalagi
menurunkan ketinggian disekitar Gunung Salak, hal ini banyak mengandung resiko.
Persyaratan untuk menurunkan
ketinggian dan terbang rendah Visual Flight Rule (VFR) yaitu jarak pandang
(Visibility), penerbang harus dapat melihat dengan jelas objek di depan pesawat
seperti gunung, pohon, tiang, menara, kabel tegangan tinggi dll. Kalau cuaca
berkabut, berawan apalagi gelap maka jangan pernah melakukan terbang rendah
(VFR) tetapi tetap lakukan terbang IFR.
Sungguhpun penerbang ingin dan ngotot
untuk terbang rendah pada cuaca berkabut/berawan (Low Visibility), maka
seharusnya Air Traffic Controller (ATC) personnel melarangnya dan seharusnya
ATC melakukan diskusi yang intensif terlebih dahulu dengan penerbang sebelum
memberikan ijin kepada penerbang untuk terbang rendah. Hal ini membutuhkan ATC
dengan dedikasi tinggi dalam pekerjaan karena resikonya besar dan berat dan
tidak dapat diterima kalo ada alasan bahwa tugas ATC sangat banyak (Overload) sebab itulah
tugas ATC yaitu membimbing semua pesawat yang ada didaerahnya untuk selamat
(Safe for flight).
Ada banyak persyaratan yang harus
dipenuhi untuk terbang rendah, antara lain:
- Untuk
pesawat penumpang harus dilengkapi dengan Ground Proximity Warning System
(GPWS) dan atau Terrain Awareness Warning System (TAWS) yang dapat
memberikan peringatan dini kepada penerbang. Penerbang harus memahami
dengan benar peralatan ini dan jangan mengabaikannya atau malahan
mematikannya (Inhibit/OFF)
- Terbang
bersama Penerbang Lokal yang mengetahui dan hafal
betul daerah tersebut, sehingga dapat memberikan saran dan jalan keluar
(way out) apabila berhadapan dengan cuaca buruk.
- Melakukan
briefing yang intensif dan mendalam sebelum terbang dengan Air Traffic
personel dan tidak diwakilkan apalagi menyuruh pihak ketiga atau orang
lain, materi briefing terutama menyangkut flight plan area dan ketinggian
terbang.
- Terbang
dengan membawa peralatan tambahan seperti :
a. GPS portable
bawaan penerbang sendiriyang dilengkapi dengan peta detail dan check point
b. Map navigasi
untuk Visual Flight Rule (Peta untuk terbang rendah dengan melihat check point
yang ada)
Hal ini sangat diperlukan terutama untuk cross check
data dengan instrument pesawat, sehingga Penerbang merasa percaya diri dan
yakin terbang aman.
Untuk fasilitas
radar (Radar Facility) selain dapat memonitor letak posisi dan ketinggian
pesawat, sebaiknya fasilitas radar juga dilengkapi dengan kontur tanah (ground
contour) sehingga radar dapat memberikan peringatan dini apabila pesawat
terbang mendekati gunung.
Demikian
disampaikan untuk menambah keselamatan terbang di Republik yang kita cintai ini
dan terucap
“MAJU TERUS DAN
JANGAN MENGULANGI KESALAHAN”.
Salam untuk
semuanya dari
Mula Fridus
Referensi tulisan :
The flight was planned under the Instrument Flight Rules (IFR)
at an altitude of 10,000 feet and the estimated elapsed time was 30 minutes
with total fuel endurance of 4 hours. The area for the demonstration flight was
over “Bogor” Area while the pilot might assume that the flight was approved to 20
Nm on radial 200 HLM VOR.
The available charts on board the aircraft did not contain
information relating to the “Bogor”Area and the nearby terrain.
The PIC acted as pilot flying while the SIC acted as pilot
monitoring during this flight. In this flight, a representative of a potential
customer sat on the observer seat (jump seat) in the cockpit.
At 0732:26 UTC, the aircraft impacted
a ridge of Mount Salak on 28 Nm HLM VOR on radial 198 at coordinate 06°42’45”S 106°44’05”E, at
approximately 6,000 feet ASL.
38 seconds prior to impact, the
Terrain Awareness Warning System (TAWS) audio warning“TERRAIN AHEAD, PULL UP”
activated once and “AVOID TERRAIN” activated 6 times.
The PIC inhibited the TAWS system
assuming that the warning was a problem on the database.
Seven seconds prior to impact, the
flight warning system audio “LANDING GEAR NOT DOWN” activated.
At 0750 UTC, the Jakarta Approach
controller on duty noticed that the flight target disappeared from the radar
monitor. There was no alert on the Jakarta Radar system prior to the
disappearance of the target.
A simulation test suggested that a
recovery action might have avoided the collision with terrain up to 24 seconds
after the first TAWS warning.
Jakarta Radar services had not
established a minimum altitude for vectoring aircraft for certain areas and the
Minimum Safe Altitude Warning (MSAW) did not provide warnings to the Jakarta
Approach controller before the aircraft impacted.
The investigation concluded that the
factors contributing to this accident were:
a. The crew were not aware of the
mountainous area surrounding the flight path due to various factors resulting
in disregarding the TAWS warning.
b. The Jakarta Radar service had not
established the minimum vectoring altitudes and the system was not equipped with
functioning MSAW for the particular area surrounding Mount Salak.
c. Distraction to the flight crew from
prolonged conversation not related to the progress of the flight resulted in
the pilot flying did not continue to change the aircraft heading while in
orbit. Consequently, the aircraft unintentionally exited the orbit.
At 0726 UTC, the pilot contacted
Jakarta Approach and requested for descent to 6,000 feet. The Jakarta Approach
controller asked the SIC to repeat the request. The SIC repeated the request for
descent to 6,000 feet. Subsequently, Jakarta Approach controller responded and
acknowledged the request by replying “6,000 copied”. The pilot replied: “Descending
to 6,000 feet”.
At 0728 UTC, the SIC requested to make
a right orbit, the Jakarta Approach controller approved the flight to make
right orbit at 6,000 feet. The Jakarta Approach controller on
duty stated that the radar display indicated that the aircraft was over WI(R)-4
Atang Sanjaya Training Area when requesting the orbit. The WI(R)-4 airspace area
extends from ground to 6,000 feet. The area was at about 17 Nm southwest of HLM
VOR.
At 0750 UTC, according to the Daily
Report provided by Air Traffic Services Operation, the controller on duty
noticed that the flight target disappeared from the radar monitor.
At 0752 UTC, the controller on duty
attempted to contact the RA 36801 flight three times.
At 0754 UTC, the Jakarta
Approach reattempted to contact the RA 36801 flight
and there was no reply.
The probable location was determined
using Jakarta Approach radar plot calculation and the SAR team used that
information to locate the accident aircraft.
The aircraft wreckage was found on a
ridge of Mount Salak on 28 Nm HLM VOR on radial
198, at approximately 6,000 feet.
During the period between 2010 and
2011, the certification test of Terrain Awareness and Warning System (TAWS)
function on the Terrain and Traffic Collision Avoidance
System (T2CAS) including bench and flight tests was performed
During the interview the controller
stated that he felt over-loaded. The Angkasa Pura II as the service
provider had no quantitative assessment on the controller
workload.
TCAS
The aircraft RRJ-95B was equipped with
Terrain and Traffic Collision Avoidance System (TCAS) which incorporates
independent Traffic Collision Avoidance System function (TCAS) and Terrain
Awareness Warning System function (TAWS). However, the TCAS system will not be
discussed in this report as this had no link to this accident. The purpose of the TAWS is to provide
terrain situational awareness aiming to prevent Controlled Flight Into Terrain
(CFIT) situations. TAWS as a situational awareness
system is not to be used as a primary navigation means of the aircraft Provide flight crew with Collision
Prediction Alerts (CPA) mode:
Warning
and Caution alert for flight into terrain.
Premature Descent Alert
Weather Information Excerpt from the
Cockpit Voice Recorder (CVR)
The CVR excerpts provided the
following information:
At 07:27:52, while the aircraft on
descent from 10,000 feet on heading 200 the SIC mentioned “dark cloud ahead”.
At 07:29:18, while the aircraft was
making an orbit, the SIC mentioned that sometimes
the ground can be seen through the clouds.
07:27:52 (SIC) Dark cloud ahead
Aircraft Heading 203°
07:27:53 –
07:28:00 Discussion between a SCAC employee and the PIC regarding to the PIC’s decision to descend. The PIC stated that his intention to descend was to prepare for the approach to runway 06, otherwise the altitude would be too high. The PIC stated that another method to lose altitude was to make an orbit.
07:28:13 (SIC) Requested to Jakarta Approach to make right orbit.
07:28:21 (APP) Approved orbit to the
right, 6,000 feet.
07:28:26 Heading set to: initially 333, then in sequence 033, 103, 150 Altitude = 7,700 feet IAS = 210 knots Aircraft performed a turn with a right bank angle of 19-20 and descends to 6,000 feet
07:28:37 –
07:28:59 The PIC demonstrated the aircraft ability for making holding pattern on the FMC
07:29:18 (SIC) Mentioned that
sometimes the ground can be seen through the clouds.
07:29:27 (PIC) Six thousand, ALT STAR.
07:30:14 Heading selector set to 174
07:30:44 The PIC demonstrated TAWS feature of “terrain” by displaying the terrain on the EFIS.
Furthermore the PIC stated “but no problem with terrain, at this moment”. Aircraft Heading 070
07:30:48 (Guest) ”Ya, it’s flat…”
07:32:58 Chime sound TAWS inhibited
07:32:58 (PIC) “may be ... data base”
07:33:19 FWS Aural warning: “Gear not down” Pulse Side Stick (SS) movement to pitch at 5 with
duration of 2 seconds resulting in autopilot disengage. The SS movement and FWS aural warning "GEAR NOT DOWN" occurred simultaneously.
07:33:20 Chime sound twice Pressing
SYS and TERR buttons
07:33:21 Trickle sound
11times Autopilot
OFF
07:33:23 (SIC) “What is
that?”
07:33:24 (PIC) Autopilot
OFF
07:33:26 End of recording
Survival Aspects
The aircraft was equipped with an
Emergency Locator Transmitter (ELT 406 MHz),
which was capable of transmitting on 3
different frequencies: 406 MHz, 121.5 MHz,
and 243 MHz.
No distress signal was received by
BASARNAS, the Australian RCC (Rescue
Coordinator Centre), Singapore RCC or
Malaysia RCC.
The ELT was found with the antenna
detached due to the high magnitude of impact
force. The separation of the antenna
from the ELT unit explained the reason why no
distress signal was transmitted
Tests and
Research
For the purposes to evaluate the
aircraft system and pilot actions on the accident
flight, a simulator test was performed
using the simulator Flight Training Devices
(FTD) at the SCAC facility in Russia.
The simulation was performed by the SCAC
and the Gromov Flight Research
Institute (Russia) test pilots.
The simulation was performed by using
FDR recording data. The route of the
accident flight was up-loaded in the
simulator FMS. The simulator TAWS was
up-loaded with a digital map of
Indonesia terrain database, the same that was
installed in the accident aircraft.
The flight simulations were performed
in automatic mode with reproduction of crew
actions in-flight, both under clear
Visual Meteorological Conditions (VMC) and
Instrument Meteorological Conditions
(IMC).
The objectives of the simulation were:
To assess
the TAWS operation particularly on the final segment of the accident
flight;
To assess
the possibility to prevent collision with the terrain by pilot action in
responding of the TAWS warning.
The results of the simulation test
were as follows:
The TAWS
was functioning properly and provided correct information to the
crew when the aircraft was in
proximity to the terrain;
The
collision could be avoided if the crew performed the appropriate actions in
response to the TAWS warning.
Conclusion of the simulator test:
The collision with the terrain could
be avoided if the crew performed the appropriate
actions in responding the TAWS warning
within 24 seconds after the first TAWS
warning activated.
PT. Indoasia Ground Utama was the
sub-contracted ground handling agency used by
Sukhoi Civil Aircraft Company to
provide services during the
promotion/demonstration flights in
Jakarta.
The services provided by the ground
handling agent was to arrange the ATC flight
plan, handling of passengers (customers)
and compiled the passenger manifest.
The investigation was not able to
obtain a copy of the actual crew and passenger
manifest. The investigation was
informed by the ground handling agency that the
original manifest and its copies were
carried on board the aircraft.
Flight Planning and Coordination
On 9 May 2012, the ground handling
agent staff member submitted the flight plans
to the briefing office for both
demonstration flights. The proposed flights were
prepared by the Navigator with the
intention to fly within a radius of 20 Nm from
Halim airport. The ground handling
agent staff member carried 3 copies of the flight
plan for each flight, one copy for the
flight crew and two copies for the briefing
office.
40
The briefing office staff did not
approve the proposed flight plans as the planned
route would interfere with the air
traffic of Soekarno-Hatta International Airport. The
briefing office staff suggested that
the flight route be revised to “Pelabuhan Ratu”
which was on the 200 radial and 50 Nm
from the HLM VOR. The suggestion was
accepted by the ground handling staff.
The flight was planned to fly at 10,000 feet
under the IFR.
The briefing office staff made a
correction to the flight plan by adding “HLMP.
Ratu-HLM”, “radial 200” and crossed
out the proposed route of “radius 20 Nm”.
Meanwhile, the ground handling staff
made a correction on his copy of the flight
plan by adding “radial 200” in the
column “route”.
Prior to the second flight, the PIC
stated that he wanted to change the route to radial
160 of HLM VOR then a right turn onto
the 200 radial. The ground handling staff
reported that he called the briefing
office and told them of the PIC’s request. The
briefing office staff could not recall
that he received such a phone call.
The Halim Tower controller on duty
heard a conversation among the briefing office
staff that the first flight was
performed over the “Bogor Area”, and assumed that the
second flight would be conducted in
the same way.
The Halim Tower controller informed
the Jakarta Approach controller, about the
intended route to the “Bogor Area” at
an altitude of 10,000 feet and this was
approved by Jakarta Approach.
The area chart was given to the crew
that was obtained from the briefing office. The
area chart did not contain any terrain
information.
The flight training area is airspace
with the limit of boundaries with minimum and
maximum allowed altitude. Atang
Sanjaya Training area / WI(R)-4 is a restricted
area/military training area located
near Bogor city. This area is commonly named as
“Bogor area”. The Atang Sanjaya
Training Area is located at 17 Nm from HLM
VOR and has a rectangular area of 7 x
20 Nm. The altitude limit of the area is from
ground level to 6,000 feet. The
airspace over the Atang Sanjaya Training Area at
altitudes above 6,000 feet is not a
military training area.
The Jakarta Flight Data Officer (FDO)
received the flight plan from the briefing
office and entered the data into the
Flight Data Edit Display (FDED). He selected the
aircraft type as Sukhoi 30 (Su-30) as
the database on the FDED did not include the
Sukhoi RRJ-95B.
After accepting the flight under his
jurisdiction, the Jakarta Approach controller on
duty wanted to know the particular
information of the flight by checking on the
FDED in his radar display. The FDED
showed that the flight was a Su-30 (Sukhoi
military aircraft). After checking
this information, the controller believed the flight
was a military Sukhoi aircraft that
was flying to the Bogor Area for a test flight. The
controller realized that the missing
aircraft was a civil aircraft Sukhoi RRJ-95B only
after he called the Halim Tower
controller.
The pilot intention to descend to
6,000 feet and subsequently make an orbit was to
lose altitude. The intended landing
runway was runway 06. The aircraft position at
that time was too high to make an
approach. This situation differed to the first
demonstration flight that landed on
runway 24.
The decision to orbit might be due to
the fact that the flight had reached the point as
approved on the flight plan as assumed
by the pilot, which was on the 200 radial and
20 Nm from the HLM VOR.
07:27:52 (SIC) “Dark cloud ahead.”
Aircraft heading was 203°.
The SIC mentioned that there was dark
cloud ahead while the aircraft was heading
towards the Mount Salak area. This indicated
that the area around Mount Salak was
cloudy.
07:28:37 - 07:28:59 The PIC
demonstrated the aircraft ability for holding using
Flight Management Computer (FMC) entry
data.
07:29:18 The SIC stated that sometimes
the ground can be seen through the
cloud.
This statement indicated that the area
around the aircraft was partially cloudy.
According to the FDR data, the area of
the orbit was over the Atang Sanjaya
Training Area.
07:30:44 The PIC demonstrated the
aircraft TAWS system feature of
“TERRAIN”. Furthermore the PIC stated
that kind of information was
not necessary at that moment. The
guest who sat in the cockpit
commented “Ya, it’s flat…”. At that
time, the FDR data showed that
the aircraft was on a heading of 070°.
The PIC demonstrated the TAWS feature
by activating the terrain display on the
EFIS. At that moment, the aircraft was
heading to the north east toward the Java Sea,
so that the terrain display might not
indicate any terrain information due to the flat
area ahead.
The PIC mentioned that the terrain
function was not necessary and it was confirmed
by the guest that it was flat. The
flat area as stated by the guest may be the area in
front of the aircraft which was
covered by TAWS on that aircraft heading.
The guest statement could have affected
the PIC’s perception that the whole area
surrounding the flight path was flat.
The reducing roll angle indicated that
the aircraft heading was close to the intended
heading. The aircraft then stopped the
turn and flew on a heading of 174° as selected
on the ‘heading selector’. At this
point, the aircraft had exited the orbit. The orbit
was initiated while the aircraft was
on heading of 200° and stopped on a heading of
174° instead of
returning to a heading of 200°. The complete 360° orbit had not
been
completed.
The PIC set the heading to 174° at 07:30:14 and
subsequently his attention was
distracted with conversation not
related to the progress of the flight. The pilots may
not have noticed that the aircraft had
exited the orbit and assumed that it was still
continuing to turn. This was evident
as at 07:31:58, the SIC mentioned that he would
make the request to Jakarta Approach
controller after the orbit was completed,
however the aircraft had stopped
turning
07:32:13 - 07:32:25 There was a
discussion between the pilots to determine the
heading to return to Halim.
It took several seconds for the SIC to
determine the direction to return to Halim. The
investigation could not determine the
reason for this. The SIC exclamations of
determining the direction to return to
Halim may have distracted the PIC.
07:32:29 The PIC commanded the SIC to
request a right turn to a heading of
020° and descent to
1,600 feet.
The intention to descend to 1,600 feet
was to descend to the Turning Altitude for the
VOR Approach to runway 06 at Halim.
At this time, the aircraft was flying
on a heading of 174° for approximately 4 Nm.
The PIC’s intention to descend
indicated that he was not aware of the mountainous
area surrounding the flight path.
In the middle of these warning
activations, the SIC asked “What is that?” This
expression could be interpreted as “Why
is that”. This expression indicated that the
SIC was surprised with the warning and
he did not expect that the warning would
activate. This indicated that the SIC
was not aware of the mountainous area
surrounding the flight path.
07:32:58 Chime (1x). FDR revealed that
the TAWS system was inhibited.
07:32:59 (PIC) “may be ... data base”.
The FDR data revealed that the SYS and
TERR button of the TAWS were switched
off. This indicated that the PIC
inhibited the TAWS system. The chime indicated the
deactivation of the TAWS. The PIC
inhibited the TAWS assuming that the warning
might be triggered by a problem with
the TAWS terrain database.
The PIC did not react appropriately to
the TAWS warnings, this indicated that he did
not appreciate the significant of the
warnings.
The aural warning of “Gear Not Down”
was from the aircraft warning system. This
warning activated whenever the
aircraft height was below 800 feet above ground
level (AGL) and the landing gear was
not down. The TAWS (GPWS) mode 04 has a
similar warning of “Too Low Gear”.
The PIC manually activated the side
stick to 5° pitch up, this action resulted in the
autopilot disengaging. The
disengagement of the autopilot was indicated by the
trickle sound warning. It was also
stated by the PIC that the autopilot was turned off.
The action of the PIC to manually fly
by operating the side stick to pitch up at 5°
could not be an indication of an
attempted escape action. Normally an escape action
requires flight control pull up,
advance engine power to go around power (TOGA)
and speed brake retract. The
investigation could not determine the reason of the
PIC’s action.
24 seconds after the first TAWS
warning (07:32:48). After this time, any pilot action
would not successfully avoid collision
with terrain.
Flight
Preparation
The proposed flight plan had been
revised and was agreed by the ground handling
and Halim briefing office staff. The
agreed flight plan was to fly to “Bogor Area”.
The proposed flight plan did not
contain information of the area and only contained
the 200 radial and 20 Nm.
The briefing office staff informed the
Halim Tower controller that the flight would
be performed in the “Bogor Area”.
Furthermore, the Halim Tower controller
informed Jakarta Approach controller
of that information.
There was a different understanding
between the pilots and the ATC relating to the
intended flight plan. Both Halim Tower
controller and the Jakarta Approach
controller understood that the flight
would be performed in the “Bogor Area”.
However, given that the previous
demonstration flight reached the point on the 200
radial at 20 Nm from HLM VOR it is
likely that the pilot believed that the second
demonstration flight was approved to
the same point.
The chart available on board the
aircraft (see figure 8) did not contain the
information of the Atang Sanjaya
Training area. Without this map the pilot may not
have been aware of the location of the
Atang Sanjaya Training area and the
surrounding mountainous area.
The incomplete briefing and inadequate
information on the flight plan suggested that
the pilot would not have been aware of
the “Bogor” area including the area
boundaries and altitude limitations.
2.3 Flight
Altitude
The flight was planned to the “Bogor”
Area at 10,000 feet under the IFR. The
“Bogor” area is located at 17 Nm from
HLM VOR within the MSA of HLM VOR
which was 6,900 feet. Beyond 25 Nm
from HLM VOR, the minimum altitude would
be the Area Minimum Altitude (AMA)
which was 13,200 feet.
The Jakarta Approach controller
checked the FDED and found information that the
flight was a Su-30 (Sukhoi military
aircraft). After checking this information, the
controller’s understanding of the
aircraft type was that it was a Sukhoi military
aircraft and that it was flying to the
“Bogor” Area for a test flight.
The Jakarta Approach controller was
not concerned about the limits of the Atang
Sanjaya Training (Bogor) area which
are from ground level up to 6,000 feet. The
Jakarta Approach controller assumed
that a military aircraft was eligible to fly in this
area. As a result, the Jakarta
Approach controller approved the aircraft to descend to
6,000 feet.
46
2.4 Minimum Safe
AltitudeWarning (MSAW)
The objective of the MSAW function is
to assist in the prevention of Controlled
Flight Into Terrain (CFIT) accidents
by generating, in a timely manner, a warning of
the possible infringement of a minimum
safe altitude.
Based on the replay of the radar
display, the evidence showed that the flight made an
orbit over the “Bogor” area (WI(R)-4)
at an altitude of 6,100 feet and the Predicted
Airspace (PAS) alert activated.
The Predicted Terrain (PTR) or Terrain
(TR) alerts were not active while the flight
was in the proximity of Mount Salak.
There was no warning to the Jakarta Approach
controller relating to the aircraft’s
position, relative to Mount Salak.
2.5 ATCWorkload
The voice recorded on the ATC ground
based recorder indicated that, in the period
prior to the accident, there was an
intensive exchange of communication between the
controller and all pilots within the
ATC area of responsibility. The communications
were performed continuously one after
another, practically without pause.
During that period, the controller was
handling 13 other aircraft. The intensive
exchange of communications required
the controller to transfer his attention quickly
from one aircraft to another. The
quick transfer of attention might have led the
controller to concentrate only on the
aircraft being communicated with.
Consequently, the aircraft under his
area of control which were not directly in radio
communication might not have been
closely monitored. This situation was one of
the factors that may have contributed
to the Jakarta Approach controller not noticing
that the Sukhoi aircraft had
disappeared from the radar screen for a period of about
24 minutes.
It was stated during interview that
the Jakarta Approach controller felt over-loaded.
At that time there were no assistants
or supervisor as stated in Advisory Circular
(AC) 69-01, so that the controller
covered the jobs of assistant, controller and
supervisor. As an Air Traffic Service
provider, the Angkasa Pura II is required to
conduct an assessment on the capacity
management including controller workload. In
order to perform such an assessment,
there are several criteria to be employed as
stated in AC 170-02 Paragraph 3.1
Capacity Management (see Appendices 6.2).
It has been broadly accepted that
adult human working memory capacity average is
seven plus or minus two unrelated items7. The term ‘working
memory’ refers to a
brain system that provides temporary
storage and manipulation of the information
necessary for such complex cognitive
tasks as language comprehension, learning,
and listening. Once the limit is
exceeded, one or more items are likely to be lost or
transposed.
The Jakarta Approach controller was
controlling 14 aircraft and performing
additional tasks as assistant and
supervisor. These additional tasks, added to the
controller workload.
7 Source
taken from “Engineering Psychology & Human Performance” author Christopher
D. Wickens & Justin G.
Hollands,
Prentice Hall, 2000.
47
2.6 Pilot
Situational Awareness
During the pre-flight briefing, the
ground handling agent briefed the navigator
concerning information on the flight
plan which had been agreed by the ground
handling agent and the briefing office
staff. The flight plan contained a statement
advising of the 200 radial at 20 Nm
from HLM VOR. There was no information
given by the ground handling agent
related to the agreed area of Atang Sanjaya
Training area (Bogor Area) to perform
the flight.
This limited information may have
given the pilot the understanding that the
approved route was toward the point on
the 200 radial at 20 Nm from HLM VOR
and return to Halim. Evidence from the
FDR data as shown on figure 14, showed that
the first and the second demonstration
flights reached this point. Understanding that
the approved route was to a point
instead of an area, may have contributed to the
pilot’s lack of awareness of the “Bogor”
area.
The area chart obtained from the
briefing office that was handed to the crew did not
contain any terrain information.
The chart available to the pilot is
shown on figure 8. This chart contains information
of the height of the mountain, but did
not depict the “Bogor Area” and had limited
terrain information.
The instrument chart, shown as figure
9, contained terrain contour and “Bogor Area”,
and the visual chart, shown as figure
10, may have provided a better understanding to
the pilot that the point they intended
to fly to was close to a mountainous area. These
charts were not carried on board the
aircraft.
At 07:30:45 when the aircraft was
turning at 6,000 feet and was passing through a
heading of 070°, there was a
discussion between the pilot and a potential customer
who was sitting on the observer seat.
The pilot demonstrated the ability of the aircraft
with the TAWS system by putting the
terrain information on the Navigation Display.
In the direction of the flight there
was no mountain visible on the display. The pilot
stated that, at that moment, the
terrain display was not necessary. The potential
customer confirmed by stating “yes,
its flat”. This information may have built an
assumption for the pilot that the area
surrounding the flight manoeuvre was flat,
since the information was given by the
TAWS and by an Indonesian who understood
the area well.
At 07:27:52 while the aircraft was
descending from 10,000 feet on a heading of 200°
the SIC stated “dark cloud ahead”. At
that time, the aircraft was heading toward the
Mount Salak area. This statement
indicated that the area of Mount Salak was covered
by dark cloud.
At 07:29:18 while the aircraft was in
the orbit area, the SIC mentioned that the
ground sometimes could be seen through
the clouds. This statement indicated that the
area where the aircraft was orbiting
was partially cloudy.
This cloud situation was confirmed by
the weather report from Darmaga BMKG
station in which the cloud base was
reported at 600 meters.
It is reasonable to conclude that the
cloud cover prevented the pilot’s being able to
see the mountainous terrain.
Due to the factors stated above, it is
likely that the pilot’s were not aware of the
mountainous terrain in the vicinity of
the flight route.
The pilot’s lack of situational
awareness may have been affected by the following
facts:
At
07:32:51 and 07:32:59, the SIC was surprised by the TAWS warnings
AVOID TERRAIN;
At
07:32:29 and 07:32:46, the PIC commanded the SIC to request heading 020
and descent to 1,600 feet twice even
though the flight was above the
mountainous area;
At
07:32:58, the PIC disengaged the TAWS SYST while the AVOID
TERRAIN warning activated assuming
that the warning may have been
triggered by a problem with the TAWS
terrain database.
