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Atx light transport jet aircraft flight crew experiences premature stick shaker while on approach to pvd.
| Attributes | |
| ACN | 158797 |
| Time | |
| Date | 199010 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : pvd |
| State Reference | RI |
| Altitude | msl bound lower : 2000 msl bound upper : 2000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : pvd |
| Operator | common carrier : air taxi |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other descent : approach other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air taxi |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 6000 flight time type : 1100 |
| ASRS Report | 158797 |
| Person 2 | |
| Affiliation | company : air taxi |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 110 flight time total : 5000 flight time type : 1400 |
| ASRS Report | 158805 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : declared emergency other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
While on a heading to intercept the ILS to runway 5R at pvd, gear down, spoilers out, 195 KIAS, just about to retract spoilers and lower flaps, stall warning, master warning and stick shaker activated. I added power to fly out of the indicated stall condition. I then reduced power to continue the approach when again the stall warning, master warning, and stick shaker activated. Again I added power to fly out of the indicated stall condition, raised the gear, retracted the spoilers and initiated a go around. Approach control vectored us out to sea where we dumped fuel to lower our landing speed and put the aircraft through extensive slow flight tests to try to determine whether we had erroneous stall warning indications or whether we had airspeed indication problems and really were about to stall out. All indications were normal and an uneventful landing was made at pvd. Subsequent maintenance checks revealed the stall warning system to be grossly out of calibration. Supplemental information from acn 158805. We also asked for the equipment to be standing by since at that point we weren't sure if there might be a problem with the airspeed indication also. After maneuvering the aircraft in different configns we determined that it was an indication problem with the angle of attack indicators and proceeded to pvd for an approach using only 20 degree flap and a 25 KT higher reference speed. There is nothing in the preflight or in the checklist for this aircraft that allows you to insure that the system is properly calibrated prior to flight. In a severe case this could cause an adverse condition in a landing confign close to ground with gusty winds. It is entirely possible to have shake pusher go on inadvertently and cause a landing short of the runway. It is also possible that the pusher would engage on takeoff and override the pilots pitch input. It is very important that these systems get calibrated properly with the correct instruments.
Original NASA ASRS Text
Title: ATX LTT JET ACFT FLT CREW EXPERIENCES PREMATURE STICK SHAKER WHILE ON APCH TO PVD.
Narrative: WHILE ON A HDG TO INTERCEPT THE ILS TO RWY 5R AT PVD, GEAR DOWN, SPOILERS OUT, 195 KIAS, JUST ABOUT TO RETRACT SPOILERS AND LOWER FLAPS, STALL WARNING, MASTER WARNING AND STICK SHAKER ACTIVATED. I ADDED PWR TO FLY OUT OF THE INDICATED STALL CONDITION. I THEN REDUCED PWR TO CONTINUE THE APCH WHEN AGAIN THE STALL WARNING, MASTER WARNING, AND STICK SHAKER ACTIVATED. AGAIN I ADDED PWR TO FLY OUT OF THE INDICATED STALL CONDITION, RAISED THE GEAR, RETRACTED THE SPOILERS AND INITIATED A GO AROUND. APCH CTL VECTORED US OUT TO SEA WHERE WE DUMPED FUEL TO LOWER OUR LNDG SPD AND PUT THE ACFT THROUGH EXTENSIVE SLOW FLT TESTS TO TRY TO DETERMINE WHETHER WE HAD ERRONEOUS STALL WARNING INDICATIONS OR WHETHER WE HAD AIRSPD INDICATION PROBS AND REALLY WERE ABOUT TO STALL OUT. ALL INDICATIONS WERE NORMAL AND AN UNEVENTFUL LNDG WAS MADE AT PVD. SUBSEQUENT MAINT CHKS REVEALED THE STALL WARNING SYS TO BE GROSSLY OUT OF CALIBRATION. SUPPLEMENTAL INFO FROM ACN 158805. WE ALSO ASKED FOR THE EQUIP TO BE STANDING BY SINCE AT THAT POINT WE WEREN'T SURE IF THERE MIGHT BE A PROB WITH THE AIRSPD INDICATION ALSO. AFTER MANEUVERING THE ACFT IN DIFFERENT CONFIGNS WE DETERMINED THAT IT WAS AN INDICATION PROB WITH THE ANGLE OF ATTACK INDICATORS AND PROCEEDED TO PVD FOR AN APCH USING ONLY 20 DEG FLAP AND A 25 KT HIGHER REF SPD. THERE IS NOTHING IN THE PREFLT OR IN THE CHKLIST FOR THIS ACFT THAT ALLOWS YOU TO INSURE THAT THE SYS IS PROPERLY CALIBRATED PRIOR TO FLT. IN A SEVERE CASE THIS COULD CAUSE AN ADVERSE CONDITION IN A LNDG CONFIGN CLOSE TO GND WITH GUSTY WINDS. IT IS ENTIRELY POSSIBLE TO HAVE SHAKE PUSHER GO ON INADVERTENTLY AND CAUSE A LNDG SHORT OF THE RWY. IT IS ALSO POSSIBLE THAT THE PUSHER WOULD ENGAGE ON TKOF AND OVERRIDE THE PLTS PITCH INPUT. IT IS VERY IMPORTANT THAT THESE SYSTEMS GET CALIBRATED PROPERLY WITH THE CORRECT INSTRUMENTS.
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.