Lagi, Penyebab Kecelakaan Mandala Air di Medan Tahun 2005

Sebuah pesawat komersial milik maskapai penerbangan Mandala Airlines jatuh di dekat Bandar Udara Polonia, Medan, Sumatra Utara, Senin (5/9/2005) pagi. Burung besi nahas itu jatuh menimpa sekitar 20 bangunan dan iring-iringan mobil di Jalan Jamin Ginting, Padang Bulan, sekitar 100 meter dari Bandara Polonia.




Pesawat jenis Boeing 737-200 yang mengangkut 109 penumpang tujuan Jakarta itu terempas beberapa saat setelah tinggal landas, sekitar pukul 10.00 WIB. Diperkirakan semua penumpang tewas. Dua di antara 109 penumpang adalah Gubernur Sumut Rizal Nurdin, mantan Gubernur Sumut Raja Inal dan anggota DPRD Sumut Abdul Haris.


Sultan Tanjung, saksi mata, menuturkan suara ledakan terdengar sangat keras. Lelaki yang mengaku berada sekitar 50 meter dari tempat kejadian mengatakan, asap langsung membumbung tinggi tak lama setelah ledakan. "Asap berasal dari ekor pesawat," kata Tanjung.


Dia menambahkan, beberap detik setelah take off, tiba-tiba bagian ekor pesawat yang sudah menempuh 50 ribu jam terbang itu menabrak tiang listrik dan jatuh menimpa deretan pertokoan serta rumah warga. Puluhan rumah dan toko yang ditimpa badan pesawat juga ikut terbakar. Beberapa pejalan kaki serta penumpang angkutan umum yang tengah melintas di Jalan Jamin Ginting turut menjadi korban.

Sejauh ini, petugas baru mengeluarkan sekitar 15 mayat, semuanya dalam kondisi mengenaskan akibat luka bakar. Seluruh mayat sudah dibawa ke Rumah Sakit Adam Malik, RS Pirngadi dan RS Polda Sumut. Sementara puluhan mayat lainnya masih terjepit di antara badan pesawat. Proses pemindahan korban agak sulit karena kondisi pesawat yang tak karuan, hanya menyisakan ekor.


Kontributor SCTV Chaerul Darma melaporkan, sampai kini, proses pencarian korban masih terus dilakukan. Besar kemungkinan jumlah korban tewas lebih dari 117 orang, belum termasuk warga setempat yang tertimpa badan pesawat bernomor penerbangan PK-RIM 091 itu.



Berdasarkan manifes penerbangan, pesawat mengangkut 117 penumpang, termasuk delapan awak. Burung besi produksi 1981 itu dipiloti Askar Timur dengan co pilot Dhaufir. Sedangkan tiga pramugari yang ikut menjadi korban masing-masing Agnes Retnariny, Novi Maulana dan Dewi Setiasih.


sumber :Liputan6.com, 

Penyebab Kecelakaan


Komite Nasional Keselamatan Transportasi menyimpulkan kecelakaan Boeing 737-200 dengan nomor registrasi PK-RIM milik Mandala Air pada 5 September 2005 di Medan, disebabkan tidak berfungsinya alat bantu gaya angkat pesawat (flap dan slat).


Akibatnya, pesawat nahas itu tidak dapat mengudara dan menabrak bangunan serta kendaraan di Jalan Ginting, Medan. "Itu kesimpulan dari hasil investigasi kami selama setahun," kata Ketua Komite Nasional Keselamatan Transportasi Setio Rahardjo.


Dalam tragedi itu, lima awak Mandala dan 95 penumpang tewas. Lima belas penumpang luka-luka dan dua orang selamat. Empat puluh sembilan penduduk sekitar ikut tewas dan 26 orang lainnya luka-luka.


Menurut dia, kemungkinan lain penyebab kecelakaan adalah prosedur pengecekan tak sesuai dengan persyaratan. Itu membuat kondisi alat bantu gaya angkat (flap) yang belum berfungsi tidak teridentifikasi. Seharusnya, kata dia, penerbang mengaktifkan suara peringatan lepas landas (takeoff warning horn). "Tapi kami tidak tahu kenapa alat ini tidak berfungsi," ujarnya.


Apabila alat peringatan lepas landas berbunyi, kata dia, sesuai dengan standar operasi, penerbang harus membatalkan lepas landas. Namun, faktanya, pesawat Mandala itu tetap lepas landas. "Pesawat tinggal landas dengan konfigurasi yang tidak memenuhi persyaratan," ujarnya.


Masalahnya, menurut dia, kualitas rekaman kotak hitam alat bantu suara (cockpit voice recorder) tidak jelas terdengar, sehingga Komite Nasional Keselamatan Transportasi kesulitan memastikan pilot tak melaksanakan prosedur tadi.


Ketua tim investigasi kecelakaan Mandala Medan, Frans Wenas, mengatakan pilot dan kopilot memiliki lisensi dan berpengalaman. Pesawat Boeing 737-200 milik Mandala itu punya sertifikasi kelaikan terbang. Muatan pesawat juga stabil dan seimbang. "Jadi pesawat yang gagal lepas landas ini bukan karena kelebihan muatan," ujarnya.


Manajemen Mandala Air berjanji akan memperbaiki dan meminimalisasi risiko kecelakaan di masa depan. Direktur Mandala Air Diono Nurjadin mengatakan Mandala telah melakukan perbaikan standardisasi kemampuan pilot dan awak pesawat. "Kami juga akan meremajakan pesawat dengan mendatangkan pesawat Airbus 320," katanya.


By : Anton Aprianto ( detik.com)


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Dan yang lagi males download dan membuka blog ini  via mobile bisa langsung dibaca dibawah ini.
Masih dalam bahasa Inggris ( lagi males memperjemahkannya, habis banyak banget)


=====================================================================
AIRCRAFT ACCIDENT REPORT 



SYNOPSIS
On 5 September 2005, at 03:15 UTC a Mandala Airlines B737-200 flight number
MDL 091, registration PK-RIM, crashed during take off from Polonia Airport, Medan,
North Sumatera. The initial phase of the takeoff from runway 23 was normal.

Following liftoff, the airplane was unable to climb away and settled back onto the
runway. It then overran the departure end of the runway, and hit several approach
lights and continued to travel through a grass area and over a small river.
It subsequently impacted several buildings and vehicles before coming to rest on a
public road about 540 m from the end of runway 23.

The investigation revealed that the aircraft was not properly configured for take-off.
The flaps screw jacks and slat actuators were not in the extended position when it
was found in the crash site and examined during investigation.

The scratch marking left at the end of runway 23’s surface and the FDR data
analysis supported this condition.
Exhaustive examination of the CVR indicated that the investigation was unable to
gain important information on what actually happened prior to and during the take-off
because the cockpit area microphone channel did not record properly.

Specifically, the investigation was unable to determine from the CVR whether the flight crew had extended the flaps and slats for take-off or whether the take-off warning horn
activated when the flaps and slats were not extended for take-off.

The disassembly examination of both engines revealed there was no defect with the
engines that contributed to the accident.
Weight and balance examination also revealed that the actual aircraft take-off weight
and center of gravity met the requirements and standards take-off performance
runway 23.

The weather itself was not a factor on this accident.
The survivors reported they left the aircraft from the rear fuselage. According to other
witnesses, the fire started a few minutes after the crash.

The lack of an access road from the airport perimeter prevented the airport rescue
and fire-fighting crews from expeditiously arriving at the crash site. This fact, coupled
with the lack of coordination with other rescue participants (other than AP II),
eventually led to fewer survivors.

From 117 persons on board flight MDL 091, 5 crews and 95 passengers on board
were killed, 15 passengers seriously injured and 2 passengers (a mother and child)
were reported survived without any injuries. There were 49 grounds fatalities and 26
grounds seriously injured.
The airplane is considered total loss due to the impact forces and post-crash fire.

1 FACTUAL INFORMATIONS
1.1 History of Flight

On 5 September 2005, at 03:15 UTC, Mandala Airlines registered PK-RIM,
operating as flight number MDL 091, a Boeing 737-200 departing for Soekarno-Hatta Airport, Jakarta from Medan.

 The previous flight was from Jakarta and arrived at Medan uneventfully. The same crew have flight schedule on the same day and returned to Jakarta. The flight was a regular
scheduled passenger flight and was attempted to take-off from Polonia Airport, Medan, North Sumatera to Jakarta and it was the second trip of the day for the crew.

At 02.40 UTC information from dispatcher, those embarking passengers,
cargo process and all flight documents were ready.
At 02.52 UTC, Mandala/MDL 091 asked for push back and start up clearance bound for Jakarta from the Air Traffic Controller/ATC, after received the approval from the ATC they began starting the engines.

At 02.56 UTC, the controller cleared MDL 091 taxi into position on runway 23 via Alpha.
At 03.02 UTC, MDL 091 received clearance for take off with additional clearance from ATC to turn left heading 120º and maintain 1500 ft.
The MDL  091 read back the clearance heading 120º and maintains 1000 ft. The ATC
corrected the clearance one thousand five hundred feet. The MDL 091 reread
back as 1500 ft.

Some of the passengers and other witnesses stated that the aircraft has lifted its nose in an up attitude and take off roll was longer than that normally made by similar airplanes. Most of them stated that the aircraft nose began to lift-off about few meters from the end of the runway. The ATC tower controller recalled that after rotation the plane began to “roll” or veer to the left and to the right.

Some witnesses on the ground recalled that the airplane left wing struck a building before it struck in the busy road, then heard two big explosions and saw the flames. Persons on board in MDL 091, 5 crew and 95 passengers were killed, 15 passengers seriously injured and 2 passengers (a mother and child) were reported survived without any injuries; and other 49 persons on ground were killed and 26 grounds were serious injured.


2 ANALYSIS
2.1 Failure to climb
The performance analysis based on the FDR data shows that the take-off profile was normal until rotation. The airplane rotated to a higher than normal attitude, climbed briefly, and stalled before settling back onto the runway.
The failure to climb is shown clearly by the scratch marks found at the end of the runway 23 as well as main landing gear tracks on the ground and grass beyond the runway end. The silvery scratch marks on the runway end indicate that the tail portion of the fuselage hit the runway.
 Moreover on this particular area there was no mark of the nose landing gear. It is solid
evidence that the aircraft failed to climb with nose-up attitude of at least 13°.

The following is a description on possible reasons for the failure to climb.
The possibilities include issues in:
• Weight and balance
• Engines
• High lift devices : Flap and slat

2.1.1 Weight & Balance
Referring to the load manifest, the actual take-off weight of 51,997 kg was 3 Kg less than the captain requested and 393 kg less than MTOW for particular condition. The load manifest shows also that aircraft weight and the CG position are sufficient to provide stability. Thus the overweight issue can be eliminated.

2.1.2 Engine
The observation of engine disassembly examination is summarized as
follows:
a. Both engines were in operational conditions before impact;
b. Both engines were damaged by impact;
c. Both engine were in high power setting at impact;
d. There was no sign of overheating on both engines;
e. The Number-1 (Left) engine S/N P 702988 hit the approach light
structures at high RPM before the final ground impact, so that the fan blades were at lower rotational speed at the time of final ground impact causing lesser damage;
f. The Number-2 (Right) engine S/N P 665485 hit the ground directly, so
that the fan blades were at higher rotational speed at impact causing
more severe damages.
The result of engines tear down shows that the engines operated at normal
performance. Therefore engines were not a contributing factor to the
accident.

2.1.3 High Lift Devices: Flaps & Slats
The recovered flapjack screws (6 out of 8) were identified. All jack screws showed that the left and right were in retract position Portion of the front spar in the area of slat #4 remained intact including the two slat #4 main tracks, the two auxiliary tracks and a portion of the slat
actuator fitting.
The slat and actuator were not recovered. The inboard main track was partially extended and could be moved by hand while the inboard auxiliary track, outboard auxiliary track and outboard main track were jammed in the fully retracted position.
The mechanism of the operation of slats shows that the slat would extend immediately after initial flap selection. Therefore it can be concluded that the slats and the flaps were in retract position.

2.2 Flap position
Field investigation found six screw jacks which indicated flaps were not extended.
There are three possibilities of why the flap did not travel to take-off configuration upon take-off preparation.
The first possibility is flap asymmetry. In the event of asymmetry flap would cause the flap system to stop flap movement. Investigation finding, that 6 screw jacks were in similar position this shows that both left and right flap was found at zero position, however, indicate that flap asymmetry was not the cause of the flap failed to travel to take -off configuration.
The second possibility is the failure of the flap system.

There is no available component of the flaps system that can be examined. No single faults were identified that could affect the independent flap actuation, flap position indication and takeoff configuration warning systems. Only limited single faults were identified that could affect two to the three systems simultaneously. In the last six months maintenance record stated that there was no problem reported related to the flap system. Therefore multiple
simultaneous faults resulting in failure of the flap actuation, flap position indication, and take off warning system is unlikely. The third possibility is the failure of the flight crew to select the flap to take-off position. Due to the lack of useable CVR recording from the cockpit area microphone, the investigation could not confirm whether the take-off checklist, which includes
flap selection, was properly done.

2.3 Take-off configuration recognition
The fact that the flaps and slats were in retracted position. This indicated that the aircraft attempted to take-off without being properly configured. This improper configuration should have activated the take off configuration warning horn to alert the pilots of the improper configuration.

2.4 Cockpit Voice Recorder
The followings are the results of CVR analysis.
1. The CAM channel of the CVR was of very poor quality.
2. The captain’s and first officer’s audio channels of the CVR appeared to
be operating normally. These channels contained only VHF transmissions, indicating that the flight crew was not using headsets to communicate
3. Contributing to the poor CAM channel quality was an excessive amount of electrically  induced noise or hum probably due to an open ground in the wiring connecting the cockpit area microphone and the CVR recorder.
4. From the CVR it is not possible to determine which pilot took control during the accident take off. On the same line there is no record/ document that mentioned the pilot flying.
5. Despite the poor quality, some cockpit sounds and information was recorded on the CAM channel of the CVR recording.
6. The aircraft’s take off warning horn “could not be heard” on the CAM channel of the CVR, even after extensive filtering of the hum and noise.
7. Several crew words, cockpit switch activations, engine noise, and cabin chime sounds heard on the CAM channel of the CVR are typically at a volume level much lower than the standard take-off warning horn of the Boeing 737-200. The typical sound of the takeoff configuration warning was not heard on the CVR CAM channel.

Nor was the stick shaker (typically as loud or louder than the takeoff warning horn) heard on the CVR CAM channel, although it should have been sounding as the aircraft lifted off the runway.Therefore it is possible that both the takeoff configuration warning and the stick shaker were sounding, but not recorded on the CVR CAM channel due to the intermittent electrical connection described in Section 1.16.2. No definite conclusions regarding the takeoff configuration warning could be drawn from the CVR.

The reason for the lack of take off configuration warning horn cannot be determined through sound analysis.
The following picture represents the superposition of sound spectrum taken from the CVR and the FDR data.

2.5 Flight Data Recorder
The followings are the results of FDR analysis.
• FDR readout result suggests that the speed increase of accident aircraft during take-off roll until rotation consistent with previous flight, this indicates that the acceleration was not the factor of the accident.
Engine tear down also concluded that the engines were in operation while impacted.
Wreckage and the FDR confirmed that the engine performance was not the cause of the failure to lift-off.
The FDR recorded altitude (static pressure), airspeed (pitot pressure), magnetic heading, normal load factor, and VHF mic keying. In addition, the FDR recorded limited internal data (e.g. pressure transducer temperature) used in the conversion of the binary data to engineering units.

The static and dynamic pressures were measured by transducers installed on the FDR itself. The pitot and static ports used are near the front of the aircraft, and plumbing is installed to convey the pressure to the rear of the aircraft where the FDR is installed.

Analysis of the data recorded on the FDR revealed that angle-of-attack corrections are required to accurately convert the recorded data to airplane altitude. The recorded altitude parameter shows the airplane initially climbed 170 ft in 5 seconds before settling back onto the runway and then climbing again to just over 100 ft AGL before the
recording ended (see Figure 1).

The recorded altitude parameter shows an unrealistic climb rate (~2000 ft/min) that is approximately double the typical climb rate for the accident conditions (weight, CG,
temperature, winds and field elevation).

Therefore, an examination was made of the recorded altitude. Flight tests of 737-200 aircraft have demonstrated that high angles-of-attack (AOA) beyond approximately 15° (i.e. beyond stick-shaker) result in reduced static pressure at the static ports. Altitude measurements made using the sensed static pressure (indicated altitude) must be corrected to account for
the effects of high AOA. The indicated altitude data recorded on the FDR does not make this correction; consequently, it is artificially high.

An aerodynamic simulation of the 737-200 was used to evaluate the accident takeoff and match the parameters recorded by the FDR. The simulation took into account flaps-up ground effect lift and high AOA effect.
The simulation calculates both pressure altitude as well as indicated altitude (that does not include the AOA effect) such as would be recorded by an FDR such as the one installed on the accident airplane.
A number of scenarios were investigated in the attempt to match the data recorded on the FDR from the accident takeoff. The best match in the simulator was obtained by using flaps 1 takeoff speeds (V1, Vr, and V2), but with the flaps retracted. The simulator match demonstrated that the airplane lifted off the runway, continued to pitch up through stick shaker to approximately 22° nose up. The resulting high AOA caused the wing to stall.
The airplane then descended and struck the runway tail first. It continued along the runway and briefly lifted off a second time before again descending and striking obstacles at and beyond the end of the runway.

Based on the AOA necessary to match the recorded FDR data, the stickshaker
should have been operating continuously during the brief intervals that the airplane was airborne.
The high AOA caused large errors in the static pressure used to determine altitude and airspeed, which in turn caused both recorded altitude and airspeed to read artificially high. The indicated altitude and airspeed modelled in the simulation are in close agreement with the altitude and airspeed recorded on the FDR. The engineering simulator was also used to match a normal flaps one takeoff recorded on the FDR from a previous flight using
the same techniques used to match the accident takeoff.
Figure 2 shows that the simulation and FDR data for the representative flaps one takeoff
(NTSB Takeoff #3) are in close agreement.

FDR plot of accident flight compared to previous flight from Medan in airspeed. Note that the airspeed of both flights are similar. Note also that the accident flight had a failure in lift-off as indicated by the trend in the pressure altitude.
FDR plot of previous flight from Medan compared to accident flight in airspeed and vertical acceleration. Note the successful lift-off as indicated by increasing in pressure altitude.



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