<< >> NASA ASRS Report 1518240, February 2018

Md-83 captain reported a CADC malfunction related to the pitot/static anti-ice system being overwhelmed by the weather conditions.

Attributes
ACN	1518240
Time
Date	201802
Local Time Of Day	1201-1800
Place
Locale Reference	ZJX.ARTCC
State Reference	FL
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	MD-83
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Air Data Computer
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter Weather / Turbulence

Narrative:

Just west of szw in the weather at FL330 the central air data computer (CADC)2 fail light illuminated on the FMS scratch pad. Following procedures we switched to CADC both on CADC1. A short time later both primary airspeeds and mach began to decay and autothrottles increased to [autothrottle] limit. I checked the standby airspeed and it was normal. We accomplished the unreliable airspeed memory item. Exited the weather and were about to [advise ATC] when everything went back to normal. Entered the weather one more time and it happened again; but quickly corrected itself. Continued flight with no further events. Pitot/static heat couldn't keep up with the weather conditions.

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Original NASA ASRS Text

Title: MD-83 Captain reported a CADC malfunction related to the pitot/static anti-ice system being overwhelmed by the weather conditions.

Narrative: Just west of SZW in the weather at FL330 the Central Air Data Computer (CADC)2 fail light illuminated on the FMS scratch pad. Following procedures we switched to CADC both on CADC1. A short time later both primary airspeeds and Mach began to decay and autothrottles increased to [autothrottle] limit. I checked the standby airspeed and it was normal. We accomplished the Unreliable Airspeed memory item. Exited the weather and were about to [advise ATC] when everything went back to normal. Entered the weather one more time and it happened again; but quickly corrected itself. Continued flight with no further events. Pitot/static heat couldn't keep up with the weather conditions.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.