The concern sheet
Text extracted from the PDF.
Revised 1/24/02 Airworthiness Concern Sheet
Full Name Solomon Hecht Title Aerospace Engineer Organization Boston ACO, ANE-150 Address 12 New England Executive Park City State ZIP Burlington, MA 01803 Telephone Number (781) 238-7159 E-mail solomon.hecht@faa.gov Make, Model, Series, Serial No.:
Harco Pitot Static Probes installed Eclipse EA 500 Part Numbers: 100435-39 and 100435-40 100435-39-001 and 100435-40-001 Reason for Airworthiness Concern:
Flight Test Experiences / Field Reports of Airspeed Miscompare have shown that the AOA portion of the Pitot/AOA mast has potentional for ice blockage due to manufacturing quality escape.
Date: May 29, 2008 FAA Description of Airworthiness Concern (Who, What, Where, When, How? Attachments: RA and appropriate data) During Flight into Known Icing (FIKI) testing airspeed disagreements (miscompare) were experienced on the Eclipse Aviation (EAC) EA500 aircraft. Additionally, 3 fielded airplanes reported similar issues within a 10 day period. Total Pressure/AOA measurements are determined by Pitot/AOA probe manufactured by the TSOA holder, Harco. The initial analysis indicates the possibility of F.O.D. causing of the disagreement from left to right side probes. Upon review of the additional data from Eclipse, Harco concluded that the blockage was occurring in the top AOA and Pitot tubes during descent. The cause has been identified as a quality escape of Pitot/AOA Mast insulating material that affects the heat transfer performance required to maintain de-icing of the AOA tubes. Behavior of a blocked AOA behaves similarly to an Altimeter and affects both the stall protection and calibration correction for the static source error. No other pitot (total pressure) errors have been noted in the fleet.
The aircraft type certification requires compliance to CFR 23.1323 for airspeed calibration, and CFR 23.1325 for altimeter calibration. In addition the aircraft is certificated with an artificial stall barrier system meeting the requirements of CFR 23.691 and stability augmentation (Yaw Damper) required by CFR 23.671. Accurate measurement of angle of attack is required for each of these systems to perform to the certification requirements.
A control program is being developed between the TC Holder (Eclipse Aviation) and the TSOA Holder (Harco) and will consist of the following elements.
1) Eclipse Aviation is issuing a Customer Pilot Communication to all EA500 operators for notification of the potential problem with increased emphasis on the relative sections of the EA500 Flight Manuals.
2) Harco is working with the Boston ACO is developing a means for EAC to field inspect the Pitot/AOA probes and identify those that posses the failure mechanism.
3) Eclipse Aviation will develop a service bulletin that will encompasses Harco’s requirements and establish a corrective timeline to maintain fleet safety.
Request for Information (Proposed Alternate Inspection/Repair Procedures, Cost Impact, Etc. Note: Any comments or replies to the FAA need to be as specific as possible. Please provide specific examples to illustrate your comments/concerns.
Attachments: *SDR(s) *A/IDS *SL(s) *SAIB *FAASR/*NTSBSR *AD *AMOC *RA Notification: FAA *AOPA *EAA Type Club *TC Holder O t h e r :
Response Requested 06/08/08: Emergency (10 days) Alert (30 days) Information (90 days) This Airworthiness Concern Sheet (ACS) is intended as a means for FAA Aviation Safety Engineers to coordinate airworthiness concerns with aircraft owner/operators through associations and type clubs. At this time, the FAA has not made a determination on what type of corrective action (if any) should be taken. The resolution of this airworthiness concern could involve an AD action or an SAIB, or the FAA could determine that no action is needed at this time. The FAA’s final determination will depend in part on the information received in response to this ACS.
The FAA endorses dissemination of this technical information to all manufacturers and requests association and type clubs comments.
*Service Difficulty Reports (SDRs); Accident/Incident Data System (A/IDS); Service Letter (SL); Special Airworthiness Information Bulletin (SAIB);
Federal Aviation Administration (FAA)/National Transportation Safety Board (NTSB) Safety Recommendation (FAASR/NTSBSR); Airworthiness Directive (AD); Alternate Method of Compliance (AMOC); Risk Assessment (RA); Aircraft Owners & Pilots Association (AOPA);
Experimental Aircraft Association (EAA); Type Certificate (TC)