Aircraft shudders (B727) while extending flaps while making approach to mci.

Attributes
ACN	360422
Time
Date	199702
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : mci
State Reference	MO
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Light	Night
Aircraft 1
Controlling Facilities	tracon : mci
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	360422
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

XX00Z. ATC frequency, 132.95. ATC facility: kansas city approach. Location, 10 NM south of mci. Level at 4000 ft 210 KTS approach control request 170 KTS right to 300 degree heading selected flaps 2 degrees at 205 KTS in a 15 degree angle of bank. All was normal then selected flaps 5 degrees. Then the aircraft started to shudder and buffet a lot. Angle of bank increased to 30 degrees. Autoplt was disengaged and the nose dropped while trying to recover and figure out what happened. We lost 400 ft. The buffeting stopped before we can call approach about our problem. She gave us 3000 ft with no other comments. After regaining control and descending to 3000 ft, all indication in the cockpit were normal. Log entry were made. The buffet were much more than the usual flaps selection at high speed. We have no idea what might have caused this.

Original NASA ASRS Text

Title: ACFT SHUDDERS (B727) WHILE EXTENDING FLAPS WHILE MAKING APCH TO MCI.

Narrative: XX00Z. ATC FREQ, 132.95. ATC FACILITY: KANSAS CITY APCH. LOCATION, 10 NM S OF MCI. LEVEL AT 4000 FT 210 KTS APCH CTL REQUEST 170 KTS R TO 300 DEG HDG SELECTED FLAPS 2 DEGS AT 205 KTS IN A 15 DEG ANGLE OF BANK. ALL WAS NORMAL THEN SELECTED FLAPS 5 DEGS. THEN THE ACFT STARTED TO SHUDDER AND BUFFET A LOT. ANGLE OF BANK INCREASED TO 30 DEGS. AUTOPLT WAS DISENGAGED AND THE NOSE DROPPED WHILE TRYING TO RECOVER AND FIGURE OUT WHAT HAPPENED. WE LOST 400 FT. THE BUFFETING STOPPED BEFORE WE CAN CALL APCH ABOUT OUR PROB. SHE GAVE US 3000 FT WITH NO OTHER COMMENTS. AFTER REGAINING CTL AND DSNDING TO 3000 FT, ALL INDICATION IN THE COCKPIT WERE NORMAL. LOG ENTRY WERE MADE. THE BUFFET WERE MUCH MORE THAN THE USUAL FLAPS SELECTION AT HIGH SPD. WE HAVE NO IDEA WHAT MIGHT HAVE CAUSED THIS.

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.