B767 first officer reported multiple stabilizer trim anomalies.

Narrative:

This report documents a series of persistent unschd stabilizer trim EICAS messages that were received on aircraft X during my most recent pairing. The first indication was during taxi out an overnight-delayed flight. It appeared cyclically every few minutes; and [maintenance control] assisted in the clearing of the EICAS. We proceeded to ZZZ uneventfully. While taxi out of ZZZ 2 days later on ferry flight; the same EICAS appeared. Again [maintenance control] assistance cleared the caution through system resets. We gate returned and ZZZ maintenance confirmed a full system reset and that the previous cautions were nuisance only. At no time was actual stabilizer trim movement observed; and we elected to takeoff for ZZZ1. The unschd stabilizer trim caution appeared passing 12;000 feet and began cycling on and off every few minutes; never staying on for more than a few seconds. We consulted the QRH; but as no actual trim movement was noted and the cautions were momentary; we did not run the procedure. Consultation with dispatch resulted in a non-emergency divert to ZZZ2. After mechanics and parts were flown in to ZZZ2; we attempted to fly [back to ZZZ1 on the] ferry flight. Again the unschd stabilizer trim EICAS appeared; this time with engines off during the before pushback checklist; and the flight canceled. One more attempt by our crew was made to fly [the next day]; but flight was canceled pending further maintenance.

Original NASA ASRS Text

Title: B767 First Officer reported multiple Stabilizer Trim anomalies.

Narrative: This report documents a series of persistent UNSCHD STAB TRIM EICAS messages that were received on Aircraft X during my most recent pairing. The first indication was during taxi out an overnight-delayed flight. It appeared cyclically every few minutes; and [Maintenance Control] assisted in the clearing of the EICAS. We proceeded to ZZZ uneventfully. While taxi out of ZZZ 2 days later on ferry flight; the same EICAS appeared. Again [Maintenance Control] assistance cleared the caution through system resets. We gate returned and ZZZ maintenance confirmed a full system reset and that the previous cautions were nuisance only. At no time was actual stabilizer trim movement observed; and we elected to takeoff for ZZZ1. The UNSCHD STAB TRIM caution appeared passing 12;000 feet and began cycling on and off every few minutes; never staying on for more than a few seconds. We consulted the QRH; but as no actual trim movement was noted and the cautions were momentary; we did not run the procedure. Consultation with dispatch resulted in a non-emergency divert to ZZZ2. After mechanics and parts were flown in to ZZZ2; we attempted to fly [back to ZZZ1 on the] ferry flight. Again the UNSCHD STAB TRIM EICAS appeared; this time with engines off during the before pushback checklist; and the flight canceled. One more attempt by our crew was made to fly [the next day]; but flight was canceled pending further maintenance.

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.

Attributes
ACN	1668563
Time
Date	201907
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Horizontal Stabilizer Trim
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 151 Flight Crew Total 10145 Flight Crew Type 7091
Events
Anomaly	Aircraft Equipment Problem Less Severe