Cessna Fuel Stabilisation

Full document text

AIRWORTHINESS BULLETIN AWB 28-006 Issue : 1 Cessna Fuel Stabilisation Date : 31 October 2007 Page 1 of 2 1. Applicability Cessna 200 Series aeroplanes to which a CASA Airworthiness Directive Titled: “Fuel Flow Stabilisation Placards” and FAA CESSNA AD 79-15-01 apply. 2. Purpose Remind operators and maintainers of the applicable Cessna 200 Model aeroplanes to periodically ensure that all placards and emergency instructions are in place as required by the documents referred to in applicable Airworthiness Directives. 3. Background A feature of the Continental Avgas fuelled engines which employ the constant-flow, fuel injection system design, is a fuel vapor purging system to ensure that solid fuel is delivered to the injectors. Under certain conditions, however, the fuel system can suffer from accumulated vapor in the fuel lines and cause unstable fuel flow which may result in rough running, power surges and, if not handled correctly, a complete loss of engine power, requiring an in-flight engine re-start. Full instructions for identifying various types of unstable fuel flow events and the proper corrective actions, are contained in Cessna Service Information Letter (SIL) SE79-25 (Supplement #1) which introduces two documents, a fixed placard and an expanded instruction card which should be within reach of the pilot at all times. This requirement is mandated by AD/CESSNA 205/14, AD/CESSNA 206/29, AD/CESSNA 207/20 and AD/CESSNA 210/41, all of which make reference to CESSNA FAA AD 79-15-01. The affected aeroplanes may not have a flight manual or Pilots Operating Handbook and therefore depend on a fixed placard and an expanded instruction card to provide the emergency operating instructions for the engine fuel system. To ensure integrity of the approved data, any system of maintenance for the aeroplane should include a periodic check to ensure that all required placards are in place. For example, for any aeroplane maintained in accordance with CASA Schedule 5, note the following extract: Section 4 - The Instruments (1), Check internal and external required placards. NOTE: Reference should be made to the aircraft flight manual and airworthiness directives for the required placards AIRWORTHINESS BULLETIN AWB 28-006 Issue : 1 Cessna Fuel Stabilisation Date : 31 October 2007 Page 2 of 2 This means, for example, that compliance with CASA AD/CESSNA 206/29 Fuel Flow Stabilisation Placard is to be checked and certified for at each periodic inspection, even though there is no repetitive requirement in the AD. Adherence to the manufacturer’s instructions will ensure that in the event of an unstable fuel flow condition being encountered, power for flight is restored as quickly as possible. 4. Recommendation CASA recommends that all operators and maintainers check that the required engine fuel operating instruction placards are in place, including the expanded instruction cards as required by the requirements of the aircraft flight manual and applicable Airworthiness Directives. 5. Enquiries Enquiries with regard to the content of this Airworthiness Bulletins should be made via the direct link e-mail address: AirworthinessBulletin@casa.gov.au Or in writing, to: Airworthiness Engineering Branch GPO Box 2005, Canberra, ACT, 2601