Coming AD Limits Operations To Day VFR Conditions

In a Customer Technical Communication notice released this week, Eclipse Aviation announced it has developed a fix for the pitot/AOA probe system on the Eclipse 500 to address icing issues, as ANN first reported in April.

Eclipse tells ANN the new configuration follows over 60 hours of developmental flight testing, and incorporates changes in the Pitot/AOA probe and aircraft tubing. The supplier for the pitot/AOA probe incorporated a drain in the tip of AOA/pitot probe, as well as added insulation and heater elements within the probe to keep temperatures inside the probe above freezing at all times.

Eclipse says the fix was tested in one of its engineering flight test aircraft at extremely low temperatures, "with complete success."

TSO documentation will be submitted by the supplier by the end of this month, according to Eclipse. A unit is now installed on a test aircraft for certification, which Eclipse hopes will be completed within three weeks. Once certified, the new system will be incorporated into the production line, and aircraft already in the field will have the piece retrofitted through issuance of a service bulletin. Eclipse aims to have the problem rectified fleet-wide by September.

The fix comes following three reported pitot icing incidents in Eclipse 500s in which pitot pressure was lost on both left and right primary air data sources, resulting in the loss of airspeed indications on the Primary Flight Displays (PFDs). All three aircraft maintained airspeed readings through a third, independent source, and recovered primary airspeed indications once the aircraft descended into warmer air.

Through testing, Eclipse found a specific set of temperature and humidity conditions which led to condensation inside the original probe, which froze as the aircraft climbed to higher altitude.

FAA Says An AD Is Coming

Until the fix is implemented, however, it appears current Eclipse owners will have to comply with increasingly tight restrictions on flight operations in their planes.

Eclipse also notified customers of a pending Airworthiness Directive from the FAA, limiting all flights to day Visual Flight Rules (VFR) conditions that do not allow the moisture in the pitot/AOA system to freeze.

This is more restrictive than the previous FAA approved limitation, which required aircraft operations to be temporarily limited to flights in Visual Meteorological Conditions (VMC) with an Eclipse company pilot or Eclipse trained mentor pilot on board. Under the coming AD, an Eclipse pilot would not be allowed to file an IFR flight plan, or ascend above FL180.

"The good news is, we expected to have all our planes retrofitted by early September," Eclipse spokesman Andrew Broom told ANN. "For now, it's not affecting very many pilots -- and we wanted to be on the forefront of this issue."

FMI: www.eclipseaviation.com