What happened
During a scheduled flight from Västerås, Sweden, to Poznan, Poland, the crew of an Airbus A320-233, registration HA-LPB, detected a strange odor in the cockpit while cruising over Kalmar county. As a precaution against potential incapacitation, the pilots intermittently used their oxygen masks. Simultaneously, two cabin crew members and one passenger experienced eye irritation and slight breathing difficulties, requiring the use of portable oxygen bottles.
The incident originated during ground operations at Stockholm/Västerås airport. Amidst heavy snowfall, the aircraft underwent de-icing procedures. During this process, de-icing fluid entered the aircraft's air conditioning and APU systems. Although the crew attempted to ventilate the cabin by running the air conditioning at high temperatures, the fluid continued to evaporate and circulate through the cabin air during the flight.
The investigation
The Swedish Accident Investigation Authority (SHK) examined the communication and procedures used during the de-ing process. The investigation found that the de-icing procedure began before the ground staff had received proper clearance from the flight crew. The investigation also looked into the training of the de-icing personnel and the oversight provided by the airline operator.
Findings
- The primary cause of the incident was a deficiency in the use of standard phraseology during communication between the ground staff and the commander.
- The de-icing operator misconstrued the commander's instructions regarding when to begin the treatment.
- The de-icing personnel lacked specific training regarding aircraft knowledge, particularly the differences in de-icing zones between Boeing and Airbus models.
- There was a lack of standardized read-back procedures during the verbal exchange between the crew and ground staff.
- The airline operator had not established a formal agreement for de-icing services with the provider and had failed to conduct necessary audits to verify the provider's compliance with safety standards.
Safety action
It is recommended that the Transport Agency, during operational checks of airports, ensures that formal agreements are in place between service purchasers and suppliers for operators conducting flights under EU-OPS 1 regulations.