A fokker 100 on initial climb at 500 ft diverted due to high N2 vibration indication on #1 engine su...

Attributes
ACN	418520
Time
Date	199810
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : aus
State Reference	TX
Altitude	agl bound lower : 500 agl bound upper : 500
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iah tower : aus tower : phx
Operator	common carrier : air carrier
Make Model Name	Fokker 100
Flight Phase	climbout : intermediate altitude climbout : initial other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	418520
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

About 500 ft into our climb off aus we received an engine #1 N2 vibration high warning on MFDU and engine vibration indicator. We cleaned up and reduced power on schedule. When power was reduced, N2 indication and MFDU checklist title returned to normal colors, while N2 remained very high, but green. Selecting alternate vibration or engine anti-ice on had no effect on the high N2 indication. When talking to the #2 flight attendant, he noted a loud abnormal groan from the left engine just after takeoff. We returned to aus as a precaution under normal conditions. Callback conversation with reporter revealed the following information: the reporter stated that after returning to aus, maintenance inspected the engine for any obvious faults but did not change any parts. The reporter said maintenance was of the opinion the problem was the #1 engine N2 vibration sensor. The reporter said maintenance decided to maintenance ferry the aircraft to ZZZ for a more intensive inspection. The reporter stated the aircraft was ferried by the reporter and copilot and during takeoff and climb could not duplicate the high N2 indication on #1 engine.

Original NASA ASRS Text

Title: A FOKKER 100 ON INITIAL CLB AT 500 FT DIVERTED DUE TO HIGH N2 VIBRATION INDICATION ON #1 ENG SUSPECTED TO BE CAUSED BY THE N2 VIBRATION SENSOR.

Narrative: ABOUT 500 FT INTO OUR CLB OFF AUS WE RECEIVED AN ENG #1 N2 VIBRATION HIGH WARNING ON MFDU AND ENG VIBRATION INDICATOR. WE CLEANED UP AND REDUCED PWR ON SCHEDULE. WHEN PWR WAS REDUCED, N2 INDICATION AND MFDU CHKLIST TITLE RETURNED TO NORMAL COLORS, WHILE N2 REMAINED VERY HIGH, BUT GREEN. SELECTING ALTERNATE VIBRATION OR ENG ANTI-ICE ON HAD NO EFFECT ON THE HIGH N2 INDICATION. WHEN TALKING TO THE #2 FLT ATTENDANT, HE NOTED A LOUD ABNORMAL GROAN FROM THE L ENG JUST AFTER TKOF. WE RETURNED TO AUS AS A PRECAUTION UNDER NORMAL CONDITIONS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT AFTER RETURNING TO AUS, MAINT INSPECTED THE ENG FOR ANY OBVIOUS FAULTS BUT DID NOT CHANGE ANY PARTS. THE RPTR SAID MAINT WAS OF THE OPINION THE PROB WAS THE #1 ENG N2 VIBRATION SENSOR. THE RPTR SAID MAINT DECIDED TO MAINT FERRY THE ACFT TO ZZZ FOR A MORE INTENSIVE INSPECTION. THE RPTR STATED THE ACFT WAS FERRIED BY THE RPTR AND COPLT AND DURING TKOF AND CLB COULD NOT DUPLICATE THE HIGH N2 INDICATION ON #1 ENG.

Data retrieved from NASA's ASRS site as of July 2007 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.

A fokker 100 on initial climb at 500 ft diverted due to high N2 vibration indication on #1 engine suspected to be caused by the N2 vibration sensor.