Gulfstream gv flight crew reported an altitude excursion and avionics issues involving the number 2 ...

Attributes
ACN	1522672
Time
Date	201802
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Gulfstream V / G500 / G550
Operating Under FAR Part	Part 91
Flight Phase	Climb
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Air Data Computer
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 23 Flight Crew Total 14000 Flight Crew Type 2840
Person 2
Function	Pilot Flying First Officer
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 6200 Flight Crew Type 1400
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance

Narrative:

On the climbout we had flight instruments disappear and the autopilot disconnect with a list of cas (crew alerting system) messages. It took a while to troubleshoot the problem; and finding out what the problem was because of confusing cas messages. After some time of selecting different air data computer's (air data computers) and comparing results with each one and the standby we determined the number 2 madc (micro air data computer) was the culprit and we took that one out of the equation and used number 1 and number 3. After that we returned to our home base with the aircraft. During the time we were troubleshooting we didn't know what data was correct and when we asked ATC what altitude they showed us at; they told us were about 1;000 ft below our assigned altitude. We compensated with standby flight instrument data and asked for a block altitude so we could be sure to be within protected airspace; and we were granted that. During our return they issued block altitudes for the time until we told them we had it sorted out and could fly the altitude we were assigned.

Original NASA ASRS Text

Title: Gulfstream GV flight crew reported an altitude excursion and avionics issues involving the Number 2 Micro Air Data Computer. Upon landing maintenance found debris in the pitot static ports.

Narrative: On the climbout we had flight instruments disappear and the autopilot disconnect with a list of CAS (Crew Alerting System) messages. It took a while to troubleshoot the problem; and finding out what the problem was because of confusing CAS messages. After some time of selecting different ADC's (Air Data Computers) and comparing results with each one and the standby we determined the Number 2 MADC (Micro Air Data Computer) was the culprit and we took that one out of the equation and used Number 1 and Number 3. After that we returned to our home base with the aircraft. During the time we were troubleshooting we didn't know what data was correct and when we asked ATC what altitude they showed us at; they told us were about 1;000 ft below our assigned altitude. We compensated with standby flight instrument data and asked for a block altitude so we could be sure to be within protected airspace; and we were granted that. During our return they issued block altitudes for the time until we told them we had it sorted out and could fly the altitude we were assigned.

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.

Gulfstream gv flight crew reported an altitude excursion and avionics issues involving the number 2 micro air data computer. Upon landing maintenance found debris in the pitot static ports.