Safety Information Bulletin Airworthiness – Operations
SIB No.: 2020-14
Issued: 05 August 2020
EASA Guidance: Return to service of aircraft from storage in relation to the COVID-19 pandemic.
All aircraft that have been stored due to the COVID-19 pandemic, continuing airworthiness management organisations (CAMOs), maintenance organisations (MOs), and competent national airworthiness authorities (NAAs).
The aviation world has been heavily hit by the COVID-19 pandemic and an unprecedented number of aircraft has been grounded. This situation has caused severe financial pressure on air operators, as well as on their service providers. Gradually, the travel restrictions in and between countries are being lifted and operators are preparing to resume passenger flights. This requires first of all that the aircraft that were put into storage for weeks or months, are being restored to an airworthy condition.
EASA has noticed an alarming trend in the number of reports of unreliable speed and altitude indications during the first flight(s) following the aircraft leaving storage, caused by contaminated air data systems. This has led to a number of Rejected Take-Off (RTO) and In-Flight Turn Back (IFTB) events. Most of the reported events concerned the accumulation of foreign objects, such as insect nests, in the pitot static system. This contamination caused obstruction of pitot probe and static port orifices, in some cases on multiple systems, even when the covers were installed. The risk of such contamination was increased, if the aircraft storage/de-storage procedures were not completely or improperly applied at the beginning, during or at the end of the storage period.
Pitot static systems provide flight critical air data information, and it is very important that the maintenance instructions of the TC holders and/or design approval holders are strictly applied. Careful planning and application of all required maintenance and the required resources by the responsible organisations is essential.
At this time, the safety concern described in this SIB is not considered to be an unsafe condition that would warrant Airworthiness Directive (AD) action under Regulation (EU) 748/2012, Part 21.A.3B, nor Safety Directive (SD) action under Regulation (EU) 965/2012, Annex II, ARO.GEN.135(c).
CAMOs and MOs are recommended to carefully follow the maintenance instructions for cleaning and inspecting the pitot static system during the return back to service of aircraft, including new and recently updated guidance/recommendations from the TC holders and/or design approval holders.
If it is suspected that there could be contamination of the air data system/pitot static probes, CAMOs and MOs should assess, if the maintenance instructions are adequate to the situation, contacting the TC holders and/or design approval holders for further instructions, as necessary.
Competent NAAs are recommended to inform, question, support and monitor the organisations under their safety oversight, and consequently to adapt their oversight of the above aspects, as necessary, during these particular circumstances.
CAMOs and MOs are also strongly recommended to consider the above referenced EASA Guidance on ‘Return to service of aircraft from storage in relation to the COVID-19 pandemic’.
For further information contact the EASA Programming and Continued Airworthiness Information Section, Certification Directorate, E-mail: ADs@easa.europa.eu.