TCASII RA leads to altitude deviation for air carrier medium large transport in cruise at FL270.

Attributes
ACN	176008
Time
Date	199104
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : cae
State Reference	SC
Altitude	msl bound lower : 27000 msl bound upper : 27500
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 18000
ASRS Report	176008
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course
Consequence	Other
Miss Distance	vertical : 800
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation

Narrative:

In level cruise at 27000', was given vector to intercept J52 northeast of cae. That heading aimed us at buildup depicted on WX radar. Advised ZJX we were deviating 15 more degrees right (to 060 degrees). On that heading with TCAS in TA/RA automatic, had an intruder at 2 O'clock showing -800' relative altitude. TCAS announced, 'traffic, traffic,' as intruder popped up on screen. Moments later it commanded, 'climb, climb.' immediate climb was commenced at the specified 500 FPM. The altitude alerter sounded. Then TCAS announced traffic clear and we returned to altitude 27000'. ZJX did not seem to know what we were talking about when questioned. He did say an aircraft had been cleared to FL260.

Original NASA ASRS Text

Title: TCASII RA LEADS TO ALT DEVIATION FOR ACR MLG IN CRUISE AT FL270.

Narrative: IN LEVEL CRUISE AT 27000', WAS GIVEN VECTOR TO INTERCEPT J52 NE OF CAE. THAT HDG AIMED US AT BUILDUP DEPICTED ON WX RADAR. ADVISED ZJX WE WERE DEVIATING 15 MORE DEGS RIGHT (TO 060 DEGS). ON THAT HDG WITH TCAS IN TA/RA AUTO, HAD AN INTRUDER AT 2 O'CLOCK SHOWING -800' RELATIVE ALT. TCAS ANNOUNCED, 'TFC, TFC,' AS INTRUDER POPPED UP ON SCREEN. MOMENTS LATER IT COMMANDED, 'CLB, CLB.' IMMEDIATE CLB WAS COMMENCED AT THE SPECIFIED 500 FPM. THE ALT ALERTER SOUNDED. THEN TCAS ANNOUNCED TFC CLR AND WE RETURNED TO ALT 27000'. ZJX DID NOT SEEM TO KNOW WHAT WE WERE TALKING ABOUT WHEN QUESTIONED. HE DID SAY AN ACFT HAD BEEN CLRED TO FL260.

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.