A C560 first officer is not familiar with the use of a GPS constant angle descent.

Attributes
ACN	631333
Time
Date	200409
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : geg.airport
State Reference	WA
Altitude	agl single value : 3800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : geg.tower
Operator	general aviation : personal
Make Model Name	Citation V
Operating Under FAR Part	Part 91
Navigation In Use	other other
Flight Phase	descent : approach
Route In Use	approach : instrument non precision
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : first officer
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 100 flight time total : 20000 flight time type : 200
ASRS Report	631333
Person 2
Affiliation	other
Function	flight crew : captain oversight : pic
Events
Anomaly	other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

Being new to GPS approachs, I interpreted the constant angle descent from the FAF to the runway as clearance to the MDA. All other non precision approachs, if an intermediate level off is required, will display a step-down (level off) on the profile view, to draw attention to that fact. Since none appeared on this GPS approach, I assumed my descent was legal. From a human factors standpoint, any time an intermediate level off is required, the profile view should reflect that level off prior to the crossing fix.

Original NASA ASRS Text

Title: A C560 FO IS NOT FAMILIAR WITH THE USE OF A GPS CONSTANT ANGLE DSCNT.

Narrative: BEING NEW TO GPS APCHS, I INTERPED THE CONSTANT ANGLE DSCNT FROM THE FAF TO THE RWY AS CLRNC TO THE MDA. ALL OTHER NON PRECISION APCHS, IF AN INTERMEDIATE LEVEL OFF IS REQUIRED, WILL DISPLAY A STEP-DOWN (LEVEL OFF) ON THE PROFILE VIEW, TO DRAW ATTN TO THAT FACT. SINCE NONE APPEARED ON THIS GPS APCH, I ASSUMED MY DSCNT WAS LEGAL. FROM A HUMAN FACTORS STANDPOINT, ANY TIME AN INTERMEDIATE LEVEL OFF IS REQUIRED, THE PROFILE VIEW SHOULD REFLECT THAT LEVEL OFF PRIOR TO THE XING FIX.

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.