Medium large transport experiences clearance confusion, has TCASII alert of traffic same altitude.

Attributes
ACN	266722
Time
Date	199403
Day	Thu
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : pmd
State Reference	CA
Altitude	msl bound lower : 13000 msl bound upper : 14000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	tower : hut
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	enroute airway : edw
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : instrument
Experience	flight time last 90 days : 100 flight time total : 7000 flight time type : 270
ASRS Report	266722
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 45 flight time total : 3000 flight time type : 500
ASRS Report	266489
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	none taken : insufficient time
Consequence	Other
Miss Distance	horizontal : 18000 vertical : 0
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

We were cleared to cross at or above 14000 ft 10 east of pmd VOR. Before reaching 14000 ft we were cleared to cross pmd VOR at 13000 ft. We reached 13000 ft. Prior to 10 DME east of pmd we were in level flight and passed a light twin at 13000 ft at least 3 mi away as shown on our TCASII -- maybe even 5 mi. We did not understand or overlooked the 14000 ft at 10 mi and flew through that altitude when cleared to 13000 ft. We are very busy in the md-80. I don't know if we made an error or not. More thought must be put into this procedure in the future by cockpit crews. I will brief this from now on. Supplemental information from acn 266489: both aircraft had the other in sight. We received a TCASII TA. The 3 step clearance confused us. I do not know for sure if our clearance was at 14000 ft 10 east of pmd or at/or below.

Original NASA ASRS Text

Title: MLG EXPERIENCES CLRNC CONFUSION, HAS TCASII ALERT OF TFC SAME ALT.

Narrative: WE WERE CLRED TO CROSS AT OR ABOVE 14000 FT 10 E OF PMD VOR. BEFORE REACHING 14000 FT WE WERE CLRED TO CROSS PMD VOR AT 13000 FT. WE REACHED 13000 FT. PRIOR TO 10 DME E OF PMD WE WERE IN LEVEL FLT AND PASSED A LIGHT TWIN AT 13000 FT AT LEAST 3 MI AWAY AS SHOWN ON OUR TCASII -- MAYBE EVEN 5 MI. WE DID NOT UNDERSTAND OR OVERLOOKED THE 14000 FT AT 10 MI AND FLEW THROUGH THAT ALT WHEN CLRED TO 13000 FT. WE ARE VERY BUSY IN THE MD-80. I DON'T KNOW IF WE MADE AN ERROR OR NOT. MORE THOUGHT MUST BE PUT INTO THIS PROC IN THE FUTURE BY COCKPIT CREWS. I WILL BRIEF THIS FROM NOW ON. SUPPLEMENTAL INFO FROM ACN 266489: BOTH ACFT HAD THE OTHER IN SIGHT. WE RECEIVED A TCASII TA. THE 3 STEP CLRNC CONFUSED US. I DO NOT KNOW FOR SURE IF OUR CLRNC WAS AT 14000 FT 10 E OF PMD OR AT/OR BELOW.

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.