ANALISIS KEGAGALAN DAN PREDIKSI UMUR PAKAI FLOW CONTROL VALVE AIRBUS A320 MENGGUNAKAN DISTRIBUSI WEIBULL

PACK Flow Control Valve (FCV) merupakan komponen penting pada sistem Air
Conditioning PACK pesawat Airbus A320 yang berfungsi mengatur aliran bleed air
bertekanan dan bertemperatur tinggi sebelum udara diproses dan didistribusikan ke
kabin. Keandalan komponen ini berpengaruh terhadap kemampuan sistem air
conditioning dan pressurization dalam menjaga temperatur, tekanan, serta sirkulasi
udara kabin selama penerbangan. Kegagalan FCV dapat menimbulkan PACK
regulation fault, menurunkan redundansi sistem, dan menyebabkan pelepasan
komponen di luar jadwal perawatan atau unscheduled removal. Penelitian ini
bertujuan menentukan karakteristik kegagalan, Mean Time to Failure (MTTF),
tingkat keandalan, Cumulative Distribution Function (CDF), failure rate, prediksi
umur pakai, serta usulan interval preventive maintenance pada PACK Flow Control
Valve P/N 1806D0000-01 yang digunakan pada pesawat Airbus A320. Penelitian
menggunakan metode deskriptif kuantitatif dengan pendekatan Distribusi Weibull
dua parameter, yaitu shape parameter (β) dan scale parameter (η). Data yang
digunakan berupa 41 kejadian unscheduled removal dan Time to Failure (TTF)
periode 2020–2025 yang diperoleh dari PT. GMF AeroAsia. Nilai TTF
menggunakan Time Since Installation karena menunjukkan lama operasi komponen
sejak dipasang hingga mengalami kegagalan dan dilepas secara tidak terjadwal.
Data TTF berada pada rentang 928 FH hingga 29.774 FH, dengan rata-rata sebesar
15.608,63 FH. Pengolahan data dilakukan melalui pengurutan TTF, penentuan
adjusted rank, perhitungan Benard’s Median Rank, transformasi variabel X dan Y,
serta regresi linier untuk memperoleh parameter Weibull. Hasil analisis
menunjukkan shape parameter sebesar 2,015375676 dan scale parameter sebesar
18.009,99 flight hours (FH). Nilai β lebih besar dari satu menunjukkan bahwa
komponen memiliki pola kegagalan wear-out, sehingga laju kegagalan meningkat
seiring bertambahnya waktu operasi. Secara teknis, kondisi tersebut dapat
dipengaruhi oleh siklus pembukaan dan penutupan katup, paparan perubahan
tekanan dan temperatur udara pneumatik, keausan bagian bergerak, penurunan
kemampuan seal, peningkatan gesekan, kebocoran internal, dan perlambataniii
respons katup. Nilai MTTF diperoleh sebesar 15.958,83 FH. Pada umur tersebut,
reliability komponen sebesar 45,67%, sedangkan CDF sebesar 54,33%. Hasil ini
menunjukkan bahwa pada saat mencapai MTTF, sekitar 54,33% populasi komponen
diperkirakan telah mengalami kegagalan dan sekitar 45,67% masih mampu
beroperasi. Failure rate pada saat MTTF sebesar 0,00009897 kegagalan per FH
atau sekitar 0,0099% per FH. Analisis B-Life menghasilkan nilai B10 sebesar
5.896,31 FH, B20 sebesar 8.556,39 FH, dan B30 sebesar 10.798,36 FH. Nilai B30
menunjukkan bahwa 30% populasi komponen diperkirakan telah gagal, sedangkan
70% lainnya masih beroperasi. Oleh karena itu, pemeriksaan fungsional atau
operasional diusulkan pada kisaran 10.800 FH, disertai monitoring awal pada
5.800–6.000 FH. Evaluasi penggantian terencana dapat dipertimbangkan sebelum
15.500 FH apabila ditemukan repetitive fault, degradasi, atau kondisi abnormal.
Penerapan perawatan berbasis keandalan ini diharapkan mengurangi unscheduled
removal, meningkatkan dispatch reliability, dan mendukung keandalan sistem Air
Conditioning PACK Airbus A320. Hasil penelitian juga menegaskan bahwa MTTF
tidak tepat digunakan secara langsung sebagai batas penggantian karena pada titik
tersebut tingkat keandalan telah menurun cukup besar. Pendekatan B30 dinilai lebih
konservatif untuk menentukan waktu pemeriksaan awal sebelum risiko kegagalan
kumulatif melampaui 30%. Meskipun demikian, penerapan interval yang diusulkan
tetap harus melalui evaluasi engineering, mempertimbangkan kondisi aktual
komponen, riwayat kerusakan armada, ketentuan Aircraft Maintenance Manual,
Minimum Equipment List, program perawatan yang disetujui, dan prosedur operator
secara menyeluruh.

PACK Flow Control Valve (FCV) is an important component of the Air Conditioning
PACK system on the Airbus A320 aircraft. It functions to regulate the flow of highpressure and high-temperature bleed air before the air is processed and distributed
to the cabin. The reliability of this component affects the ability of the air
conditioning and pressurization systems to maintain cabin temperature, pressure,
and air circulation during flight. Failure of the FCV may cause a PACK regulation
fault, reduce system redundancy, and result in component removal outside the
scheduled maintenance program or unscheduled removal. This study aims to
determine the failure characteristics, Mean Time to Failure (MTTF), reliability
level, Cumulative Distribution Function (CDF), failure rate, service-life prediction,
and proposed preventive maintenance intervals for the PACK Flow Control Valve
P/N 1806D0000-01 used on Airbus A320 aircraft. This study applies a quantitative
descriptive method using a two-parameter Weibull Distribution approach,
consisting of the shape parameter (β) and scale parameter (η). The data consist of
41 unscheduled removal events and Time to Failure (TTF) records from 2020–2025
obtained from PT GMF AeroAsia. The TTF values are based on Time Since
Installation because they represent the operating time of the component from
installation until failure and unscheduled removal. The TTF data range from 928
FH to 29,774 FH, with an average of 15,608.63 FH. Data processing was carried
out by sorting the TTF values, determining the adjusted rank, calculating Benard’s
Median Rank, transforming the X and Y variables, and performing linear regression
to obtain the Weibull parameters. The analysis resulted in a shape parameter of
2.015375676 and a scale parameter of 18,009.99 flight hours (FH). A β value
greater than one indicates that the component exhibits a wear-out failure pattern,
in which the failure rate increases with operating time. Technically, this condition
may be influenced by repeated valve opening and closing cycles, exposure to
changes in pneumatic air pressure and temperature, wear of moving parts,
deterioration of seal performance, increased friction, internal leakage, and slower
valve response. The MTTF was calculated at 15,958.83 FH. At this operating time,
the component reliability is 45.67%, while the CDF is 54.33%. This indicates thatv
at the MTTF point, approximately 54.33% of the component population is estimated
to have failed, while approximately 45.67% remains operational. The failure rate
at the MTTF is 0.00009897 failures per FH, or approximately 0.0099% per FH.
The B-Life analysis resulted in B10 of 5,896.31 FH, B20 of 8,556.39 FH, and B30
of 10,798.36 FH. The B30 value indicates that 30% of the component population is
estimated to have failed, while the remaining 70% is still operating. Therefore, a
functional or operational inspection is proposed at approximately 10,800 FH,
accompanied by initial monitoring at 5,800–6,000 FH. Planned replacement
evaluation may be considered before 15,500 FH if repetitive faults, degradation, or
abnormal conditions are identified. The implementation of reliability-based
maintenance is expected to reduce unscheduled removals, improve dispatch
reliability, and support the reliability of the Airbus A320 Air Conditioning PACK
system. The results also confirm that MTTF is not appropriate to be used directly
as a replacement limit because the reliability level has significantly decreased at
that point. The B30 approach is considered more conservative for determining an
initial inspection interval before the cumulative probability of failure exceeds 30%.
Nevertheless, implementation of the proposed interval should still undergo
engineering evaluation by considering the actual component condition, fleet failure
history, requirements of the Aircraft Maintenance Manual, Minimum Equipment
List, approved maintenance program, and applicable operator procedures