PIA A320 near Lahore on Oct 11th 2017, cargo smoke indication

Last Update: May 9, 2019 / 15:59:53 GMT/Zulu time

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Incident Facts

Date of incident
Oct 11, 2017

Classification
Incident

Cause
Cargo smoke indication

Airline
PIA Pakistan International Airlines

Flight number
PK-755

Departure
Sialkot, Pakistan

Destination
Riyadh, Saudi Arabia

Aircraft Registration
AP-BLU

Aircraft Type
Airbus A320

ICAO Type Designator
A320

A PIA Pakistan International Airlines Airbus A320-200, registration AP-BLU performing flight PK-755 from Sialkot (Pakistan) to Riyadh (Saudi Arabia), was climbing through FL140 out of Sialkot when the crew received a cargo smoke indication and decided to divert to Lahore (Pakistan) where the aircraft landed safely about 25 minutes after departure. The crew instructed emergency services to not open the cargo hold until all passengers had disembarked. After all passengers had disembarked emergency services checked the hold and found no trace of fire, heat or smoke.

The airline reported the crew followed standard procedures and discharged the fire suppression into the cargo hold. After landing the cargo hold was examined, no evidence of fire or smoke was discovered, some malfunction of the smoke detector is being suspected. Other than many Pakistani media reported there had been no (engine) fire and no smoke or smell of smoke on board.

A replacement A320-200 registration AP-BLC reached Riyadh with a delay of 8 hours.

On Nov 2nd 2017 Pakistan's SIB (PSIB) reported the occurrence was rated a serious incident and is being investigated. According to the pilots an ECAM aft cargo smoke warning appeared during initial climb, the ECAM actions were carried out and the aircraft diverted to Lahore. No signs of actual fire were observed after the aircraft was shut down.

The occurrence aircraft returned to service after about 13 hours on the ground.

On May 9th 2019 the PSIB released their final report concluding the probable causes of the serious incident were:

- Loading / placing of the chemically treated leather goods in the AFT Cargo compartment with a possible in-adequate packing.

- HI-LIFE of the smoke detectors before getting due for an overhaul / cleaning.

- High humidity level (70%) at the time of departure from Sialkot.

The PSIB found: "The reported smoke warning was a false alarm and there were no signs of actual fire, smoke or heat inside the cargo area."

The PSIB complained: "The tear down examination of the removed 04 components couldn’t be performed because the components weren’t provided to BEA, France contrary to the instructions issued by SIB, Pakistan. The components were sent for routine repair / cleaning by PIAC which lead to loss of the evidence. Consequently, the investigation process had to be prematurely ceased."

The PSIB reported the forward and aft #1 cargo smoke detectors had been in service for 17,258 flight hours, the aft #2 cargo smoke detector 13,526 hours. The smoke detectors are due for replacement at 18,000 hours.

The smoke detectors were sent for examination and performed satisfactorily.

The PSIB analysed:

As per Airbus ISI # 26.10.00004, the contamination of smoke detectors by dust, textile fibers, and particles floating in the air can lead to:

- Spurious warning.

- A significant decrease of the smoke detector sensitivity due to the background caused by the contamination.

- A loss of smoke detection function.

As per another reference (Airbus ISI #26.10.00007), the smoke detection system can create false alarm without an actual fire / smoke. Such spurious smoke warnings can occur due to following reasons:

- Use of spray in cabin / cargo compartment.
- Contamination of the smoke detectors.
- Extreme condensation / humidity / dust.
- Bleed air oil vapor.
- Entrapment of fumes in cargo compartment (smoke / fumes from the ground handling equipment).
- Terrestrial fires.
- Ingestion of anti-ice / de-icing fluids into bleed air system.
- Ingestion of engine cleaning agent into the ECS.

During this flight, 444 Kg cargo of horse bridle (a chemically treated item) was placed in rear cargo compartment. Such chemically treated goods (if not adequately packed) can contaminate the environment surrounding the smoke sensors installed in the cargo compartments.

As mentioned above, high humidity can also cause a spurious warning. The humidity factor at Sialkot at the time of departure was above 70%.