An A320 PIC questions the validity of the charting and the SID procedure as depicted on the maxxo one chart when on an indeterminate heading that was not accepted by flight crew as a vector, when 183 mi northeast of iwa VORTAC, az.

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Attributes
ACN	617132
Time
Date	200405
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : iwa.vortac
State Reference	AZ
Altitude	msl single value : 29000
Environment
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab.artcc
Operator	common carrier : air carrier
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude climbout : vacating altitude
Route In Use	departure sid : maxxo
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zab.artcc
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	climbout : vacating altitude climbout : intermediate altitude
Route In Use	departure sid : maxxon
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time total : 17000 flight time type : 3000
ASRS Report	617132
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure other spatial deviation
Independent Detector	other flight crewa other flight crewb
Resolutory Action	other
Supplementary
Problem Areas	Aircraft ATC Human Performance Chart Or Publication Flight Crew Human Performance Company
Primary Problem	Flight Crew Human Performance
Situations
ATC Facility	procedure or policy : zab.artcc
Chart	sid : maxxo one

Narrative:

After adyan on maxxo one, we inquired twice as to how long we would be on the 055 degree heading. The second time we asked, we were closing on the sjn 078 degree radial, and the controller cleared us direct cnx. I do not believe any clearance deviation occurred. However the departure procedure chart is ambiguous, in that it shows a radar vector symbol after adyan, and the text states radar vector to join sjn 078 degree radial. The radar vector is not issued by the controller, so how can it be a radar vector? Also, the FMGC (flight management guidance computer), when this departure procedure is selected from the database, will not intercept the sjn 078 degree radial. I think the fact that the aircraft behind us (another air carrier) experienced almost identical confusion illustrates the ambiguity of this departure procedure chart.

Original NASA ASRS Text

Title: AN A320 PIC QUESTIONS THE VALIDITY OF THE CHARTING AND THE SID PROC AS DEPICTED ON THE MAXXO ONE CHART WHEN ON AN INDETERMINATE HDG THAT WAS NOT ACCEPTED BY FLT CREW AS A VECTOR, WHEN 183 MI NE OF IWA VORTAC, AZ.

Narrative: AFTER ADYAN ON MAXXO ONE, WE INQUIRED TWICE AS TO HOW LONG WE WOULD BE ON THE 055 DEG HDG. THE SECOND TIME WE ASKED, WE WERE CLOSING ON THE SJN 078 DEG RADIAL, AND THE CTLR CLRED US DIRECT CNX. I DO NOT BELIEVE ANY CLRNC DEV OCCURRED. HOWEVER THE DEP PROC CHART IS AMBIGUOUS, IN THAT IT SHOWS A RADAR VECTOR SYMBOL AFTER ADYAN, AND THE TEXT STATES RADAR VECTOR TO JOIN SJN 078 DEG RADIAL. THE RADAR VECTOR IS NOT ISSUED BY THE CTLR, SO HOW CAN IT BE A RADAR VECTOR? ALSO, THE FMGC (FLT MGMNT GUIDANCE COMPUTER), WHEN THIS DEP PROC IS SELECTED FROM THE DATABASE, WILL NOT INTERCEPT THE SJN 078 DEG RADIAL. I THINK THE FACT THAT THE ACFT BEHIND US (ANOTHER ACR) EXPERIENCED ALMOST IDENTICAL CONFUSION ILLUSTRATES THE AMBIGUITY OF THIS DEP PROC CHART.

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.