Narrative:

During a WX divert from ZZZ1 (due to thunderstorms) to ZZZ2 I noticed a momentary N1; overspd on engine #2. I immediately retarded the throttle (autothrottles were engaged). Due to high cockpit workload and immediate need to avoid nearby WX; my attention was directly back to heading; airspeed; and short-distance WX deviation/avoidance. This is the best of my recollection as to when exactly the overspd most likely occurred; although I am not 100% certain. The procedure for such an event calls for a 'download' of engine data (from the engine instrument panel) prior to shutdown of the #2 engine. In the business of the short divert (routine; ATC clearance; WX avoidance; briefing to an unfamiliar airfield; communications with flight attendant; iax; ATC; and company; followed by arriving at a field with unknown support or services); I failed to recall the need to accomplish the checklist. We did; however; accomplish the checklist after shutting down the engine and prior to departing back to ZZZ1. Maintenance discovered a windshear event (4000 ft pressure altitude change) at the time of N1 overspd. Human factors: poor communication and CRM coupled with high cockpit workload; poor rest during previous layover; and failure to immediately recall need to accomplish the checklist prior to engine shutdown. I recalled the momentary exceedance after shutdown and postflt duties had been accomplished.

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Original NASA ASRS Text

Title: A MD90'S #2 ENG EXCEEDED N1 AND EGT LIMITS. WX AVOIDANCE; TASK OVERLOAD AND FATIGUE CAUSED THE CREW TO MISS THE EVENT IN FLT. DURING POST FLT THE EXCEEDANCE WAS NOTED ALONG WITH A 4000 FT PRESSURE CHANGE WIND SHEAR.

Narrative: DURING A WX DIVERT FROM ZZZ1 (DUE TO TSTMS) TO ZZZ2 I NOTICED A MOMENTARY N1; OVERSPD ON ENG #2. I IMMEDIATELY RETARDED THE THROTTLE (AUTOTHROTTLES WERE ENGAGED). DUE TO HIGH COCKPIT WORKLOAD AND IMMEDIATE NEED TO AVOID NEARBY WX; MY ATTN WAS DIRECTLY BACK TO HDG; AIRSPD; AND SHORT-DISTANCE WX DEV/AVOIDANCE. THIS IS THE BEST OF MY RECOLLECTION AS TO WHEN EXACTLY THE OVERSPD MOST LIKELY OCCURRED; ALTHOUGH I AM NOT 100% CERTAIN. THE PROC FOR SUCH AN EVENT CALLS FOR A 'DOWNLOAD' OF ENG DATA (FROM THE ENG INST PANEL) PRIOR TO SHUTDOWN OF THE #2 ENG. IN THE BUSINESS OF THE SHORT DIVERT (ROUTINE; ATC CLRNC; WX AVOIDANCE; BRIEFING TO AN UNFAMILIAR AIRFIELD; COMS WITH FLT ATTENDANT; IAX; ATC; AND COMPANY; FOLLOWED BY ARRIVING AT A FIELD WITH UNKNOWN SUPPORT OR SVCS); I FAILED TO RECALL THE NEED TO ACCOMPLISH THE CHKLIST. WE DID; HOWEVER; ACCOMPLISH THE CHKLIST AFTER SHUTTING DOWN THE ENG AND PRIOR TO DEPARTING BACK TO ZZZ1. MAINT DISCOVERED A WINDSHEAR EVENT (4000 FT PRESSURE ALT CHANGE) AT THE TIME OF N1 OVERSPD. HUMAN FACTORS: POOR COM AND CRM COUPLED WITH HIGH COCKPIT WORKLOAD; POOR REST DURING PREVIOUS LAYOVER; AND FAILURE TO IMMEDIATELY RECALL NEED TO ACCOMPLISH THE CHKLIST PRIOR TO ENG SHUTDOWN. I RECALLED THE MOMENTARY EXCEEDANCE AFTER SHUTDOWN AND POSTFLT DUTIES HAD BEEN ACCOMPLISHED.

Data retrieved from NASA's ASRS site as of May 2009 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.