Large transport has TCASII RA at cruise.

Attributes
ACN	276024
Time
Date	199406
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : clt
State Reference	NC
Altitude	msl bound lower : 25200 msl bound upper : 26000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	DC-9 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : commercial pilot : instrument
Experience	flight time last 90 days : 150 flight time total : 5522 flight time type : 150
ASRS Report	276024
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 130 flight time total : 11500 flight time type : 2000
ASRS Report	276020
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course
Consequence	Other
Miss Distance	horizontal : 18000 vertical : 1500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

While cruising in level flight at FL260, we received a TCASII RA that commanded a descent. We followed the RA vertical speed command and descended to/leveled off at FL252 momentarily. When the TCASII system annunciated 'clear of traffic,' we climbed back to FL260. ZTL advised us of the dc-9 traffic descending at the same time we started the push-over maneuver. We believe the TCA was due to the dc-9 descending at a high rate due to turbulence at higher altitudes. At the time of the incident, we were flying a center-assigned heading of 265 degrees. Perhaps ARTCC controllers should be made more aware of possible TCASII RA's due to very high vertical closure rates.

Original NASA ASRS Text

Title: LGT HAS TCASII RA AT CRUISE.

Narrative: WHILE CRUISING IN LEVEL FLT AT FL260, WE RECEIVED A TCASII RA THAT COMMANDED A DSCNT. WE FOLLOWED THE RA VERT SPD COMMAND AND DSNDED TO/LEVELED OFF AT FL252 MOMENTARILY. WHEN THE TCASII SYS ANNUNCIATED 'CLR OF TFC,' WE CLBED BACK TO FL260. ZTL ADVISED US OF THE DC-9 TFC DSNDING AT THE SAME TIME WE STARTED THE PUSH-OVER MANEUVER. WE BELIEVE THE TCA WAS DUE TO THE DC-9 DSNDING AT A HIGH RATE DUE TO TURB AT HIGHER ALTS. AT THE TIME OF THE INCIDENT, WE WERE FLYING A CTR-ASSIGNED HDG OF 265 DEGS. PERHAPS ARTCC CTLRS SHOULD BE MADE MORE AWARE OF POSSIBLE TCASII RA'S DUE TO VERY HIGH VERT CLOSURE RATES.

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.