Flight crew of air carrier light transport aircraft descended prematurely during the transition phas...

Attributes
ACN	205136
Time
Date	199202
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : eos airport : jln
State Reference	MO
Altitude	msl bound lower : 3300 msl bound upper : 4100
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 320 flight time total : 1350
ASRS Report	205136
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Air carrier flight #X was beginning approach (localizer back course runway 31) at joplin regional airport in joplin, mo. ZKC cleared flight X to descend to 5000 ft while proceeding direct to neosho for the neosho transition to localizer back course 31 at joplin. Approximately 10 mi south of neosho center cleared X to 4100 ft and said for X to maintain 4100 ft until established on the approach, cleared back course runway 31 at joplin. My captain replied by saying X cleared back course 31 approach at joplin we are going to do the neosho transition. Center did not respond. After we passed neosho VOR we began descent from 4100 MSL down to 2800 ft (labeled on approach - neosho transition nopt min altitude prior to FAF). When we were approximately 5 mi northeast of neosho on the neosho 023 degree radial, center asked us to 'say altitude.' captain responded '3300 ft.' center responded by saying our assigned altitude was 4100 until on final and that an light transport was in the area on the approach. Captain then stated that 'on the approach plate we were cleared to 2800 ft but we would climb back to 4100 ft.' the approach continued and we landed without incident. I believe that the cause of this was a miscom between center and flight X on when we were cleared to leave 4100 ft. The center wanted us to descend when on final, while we thought we were cleared to leave 4100 when we were established on the transition. My solution is simply to clarify between parties where on the approach is considered to be 'established.'

Original NASA ASRS Text

Title: FLC OF ACR LTT ACFT DSNDED PREMATURELY DURING THE TRANSITION PHASE ROUTING FOR AN INST APCH DUE TO A MISUNDERSTANDING THAT DSCNT WAS AUTHORIZED TO THE MIN ALT SHOWN FOR THE TRANSITION RTE EVEN THOUGH ATC HAD NOT PROVIDED THIS AUTHORIZATION.

Narrative: ACR FLT #X WAS BEGINNING APCH (LOC BACK COURSE RWY 31) AT JOPLIN REGIONAL ARPT IN JOPLIN, MO. ZKC CLRED FLT X TO DSND TO 5000 FT WHILE PROCEEDING DIRECT TO NEOSHO FOR THE NEOSHO TRANSITION TO LOC BACK COURSE 31 AT JOPLIN. APPROX 10 MI S OF NEOSHO CTR CLRED X TO 4100 FT AND SAID FOR X TO MAINTAIN 4100 FT UNTIL ESTABLISHED ON THE APCH, CLRED BACK COURSE RWY 31 AT JOPLIN. MY CAPT REPLIED BY SAYING X CLRED BACK COURSE 31 APCH AT JOPLIN WE ARE GOING TO DO THE NEOSHO TRANSITION. CTR DID NOT RESPOND. AFTER WE PASSED NEOSHO VOR WE BEGAN DSCNT FROM 4100 MSL DOWN TO 2800 FT (LABELED ON APCH - NEOSHO TRANSITION NOPT MIN ALT PRIOR TO FAF). WHEN WE WERE APPROX 5 MI NE OF NEOSHO ON THE NEOSHO 023 DEG RADIAL, CTR ASKED US TO 'SAY ALT.' CAPT RESPONDED '3300 FT.' CTR RESPONDED BY SAYING OUR ASSIGNED ALT WAS 4100 UNTIL ON FINAL AND THAT AN LTT WAS IN THE AREA ON THE APCH. CAPT THEN STATED THAT 'ON THE APCH PLATE WE WERE CLRED TO 2800 FT BUT WE WOULD CLB BACK TO 4100 FT.' THE APCH CONTINUED AND WE LANDED WITHOUT INCIDENT. I BELIEVE THAT THE CAUSE OF THIS WAS A MISCOM BTWN CTR AND FLT X ON WHEN WE WERE CLRED TO LEAVE 4100 FT. THE CTR WANTED US TO DSND WHEN ON FINAL, WHILE WE THOUGHT WE WERE CLRED TO LEAVE 4100 WHEN WE WERE ESTABLISHED ON THE TRANSITION. MY SOLUTION IS SIMPLY TO CLARIFY BTWN PARTIES WHERE ON THE APCH IS CONSIDERED TO BE 'ESTABLISHED.'

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.

Flight crew of air carrier light transport aircraft descended prematurely during the transition phase routing for an instrument approach due to a misunderstanding that descent was authorized to the min altitude shown for the transition route even though ATC had not provided this authorization.