MD80 departure from sea misinterped SID and turns early.

Attributes
ACN	594127
Time
Date	200309
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : sea.airport
State Reference	WA
Altitude	msl single value : 3000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : s46.tracon
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude climbout : initial
Route In Use	departure sid : mountain
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	594127
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	594125
Events
Anomaly	non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Chart Or Publication Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

The mountain 5 departure out of sea for runway 16L states 'cross D5 sea at or above 3000 ft, then turn left to a 070 degree heading for radar vectors.' I misinterped this to mean 'cross sea 5 DME at or above 3000 ft,' but to commence the turn passing 3000 ft -- not 5 DME. I began my turn to 070 degrees passing 3000 ft MSL, which was at approximately 3 DME -- not 5 DME. Sea departure control advised me of my deviation, but said there was no conflict or problem.

Original NASA ASRS Text

Title: MD80 DEP FROM SEA MISINTERPED SID AND TURNS EARLY.

Narrative: THE MOUNTAIN 5 DEP OUT OF SEA FOR RWY 16L STATES 'CROSS D5 SEA AT OR ABOVE 3000 FT, THEN TURN L TO A 070 DEG HDG FOR RADAR VECTORS.' I MISINTERPED THIS TO MEAN 'CROSS SEA 5 DME AT OR ABOVE 3000 FT,' BUT TO COMMENCE THE TURN PASSING 3000 FT -- NOT 5 DME. I BEGAN MY TURN TO 070 DEGS PASSING 3000 FT MSL, WHICH WAS AT APPROX 3 DME -- NOT 5 DME. SEA DEP CTL ADVISED ME OF MY DEV, BUT SAID THERE WAS NO CONFLICT OR PROB.

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.