Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
AIR-21-05 R1
March 29, 2021
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin is to advise registered
owners and operators of Cirrus SR22 airplanes equipped with a
turbonormalizing system per supplemental type certificate (STC)
SA10588SC of the potential loss of oil pressure due to failure of the
turbocharger oil inlet check valve.
The FAA is issuing this revision to correct the identifier of the referenced service instructions.
At this time, the airworthiness concern is not an unsafe condition that
would warrant airworthiness directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) part 39.
Background
A Cirrus SR22 was involved in an occurrence, where during cruise
flight, the pilot realized a loss in oil pressure; specifically 40 PSI
to 8 PSI in two minutes. An emergency was declared and the pilot landed
without incident. Upon inspection of the engine, the left turbocharger
oil inlet check valve was found sheared off at the threads going into
the turbo oil inlet. This caused the loss of pressure due to most of
the oil being dumped overboard.
Further investigation of the turbocharger oil inlet check valve
revealed that the check valve was overtorqued. This highlighted the
need to remind owners/operators and maintenance personnel to understand
and comply with the manufacturer’s requirements for maintaining and
operating their airplanes in an airworthy condition and to perform a
one-time check of the turbocharger oil inlet check valve for proper
installation.
Recommendations
The FAA recommends that all operators of Cirrus SR22 airplanes equipped
with a turbonormalizing system per STC SA10588SC to perform the
Accomplishment Instructions of Tornado Alley Turbo, Inc Service
Instructions TAT SI20-01, dated August 6, 2020 at the earliest
opportunity.
For Further Information Contact
Mahmood G Shah, Aerospace Engineer, 10101 Hillwood Parkway, Fort Worth,
TX 76177, United States; phone: (817) 222-5538; e-mail:
mahmood.g.shah@faa.gov.
For Related Service Information Contact