An air carrier B737 received a TCASII TA RA on a MTR that overshot his assigned altitude. The B737 responded to the TCASII RA and aircraft passed with 2 NM separation at the same altitude. Reporter questions how this can happen.

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Attributes
ACN	353092
Time
Date	199611
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : eld
State Reference	AR
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zme tower : mco
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other
Flight Plan	IFR
Aircraft 2
Operator	other
Make Model Name	Military Trainer
Operating Under FAR Part	other : other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 12600 flight time type : 800
ASRS Report	353092
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : required legal separation non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 12000 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While on level cruise FL330 J29 30 NM northeast of eld, received TA then an RA on a target at 10 O'clock 3 NM 1400 ft low and climbing. Followed RA, climbed to FL336 while first officer advised ZME. Traffic leveled off and passed behind us. We never had a visual on it because of IMC. According to TCASII cpa was 0 vertical and 2 NM horizontal. Center later informed us that it was a T1 that had been cleared to FL270. The T1 thought it was cleared to FL370. Question: how can an aircraft get 6000 ft off altitude and nobody notice? I am an even stronger believer in TCASII now.

Original NASA ASRS Text

Title: AN ACR B737 RECEIVED A TCASII TA RA ON A MTR THAT OVERSHOT HIS ASSIGNED ALT. THE B737 RESPONDED TO THE TCASII RA AND ACFT PASSED WITH 2 NM SEPARATION AT THE SAME ALT. RPTR QUESTIONS HOW THIS CAN HAPPEN.

Narrative: WHILE ON LEVEL CRUISE FL330 J29 30 NM NE OF ELD, RECEIVED TA THEN AN RA ON A TARGET AT 10 O'CLOCK 3 NM 1400 FT LOW AND CLBING. FOLLOWED RA, CLBED TO FL336 WHILE FO ADVISED ZME. TFC LEVELED OFF AND PASSED BEHIND US. WE NEVER HAD A VISUAL ON IT BECAUSE OF IMC. ACCORDING TO TCASII CPA WAS 0 VERT AND 2 NM HORIZ. CTR LATER INFORMED US THAT IT WAS A T1 THAT HAD BEEN CLRED TO FL270. THE T1 THOUGHT IT WAS CLRED TO FL370. QUESTION: HOW CAN AN ACFT GET 6000 FT OFF ALT AND NOBODY NOTICE? I AM AN EVEN STRONGER BELIEVER IN TCASII NOW.

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.