DA40 pilot reports being confused when cleared for the ILS and to maintain 2;000 ft until establishe...

Narrative:

I was receiving vectors to final for an ILS approach. Approach clearance call was something like: 'fly a heading of 250 to intercept the localizer. Cleared ILS 29R circle to land 11L. Maintain 2;000 ft until established on the localizer.' no mention was given to intercepting the glideslope; or being established on the ILS. Conditions at that point were visual except for a small cloud between me and the airport. Upon intercepting the localizer (laterally); and being in visual conditions; my thinking was that I was cleared to descend at my discretion since no mention was made to intercepting the glideslope. I assumed that the controller was aware I was in visual conditions; and I had always previously been cleared for an ILS approach with wording such as; 'maintain 2;000 ft until intercepting glideslope'; or 'maintain 2;000 ft until established on the ILS'. After a brief descent; controller asked me to state my altitude; which at that time was 1;800 ft. He told me entry to the approach was at 2;000 ft. I affirmed back that I was correcting; and climbed back up to 2;000; at which point I was then a bit above the glideslope. This then caused a more rapid attempt to correct back to glideslope; with a brief overshoot; prompting a low altitude warning from the controller. This was also rapidly corrected; at which point the controller handed me over to tower.confusion arose due to the language of; 'maintain 2;000 ft until established on the localizer'. While I know that I was cleared for the ILS; which means maintain the glideslope; during that process-intensive phase of flight; I just jumped to assume he meant established on the localizer to mean just that-laterally on the localizer (as the localizer provides no vertical guidance). A more precise phraseology; such as; 'maintain 2;000 ft until established on the ILS'; or 'maintain 2;000 ft until established on the localizer and intercepting glideslope' would be more intuitive and prevent such erroneous thinking.

Original NASA ASRS Text

Title: DA40 pilot reports being confused when cleared for the ILS and to maintain 2;000 FT until established in VMC and starts descending before glideslope intercept.

Narrative: I was receiving vectors to final for an ILS approach. Approach clearance call was something like: 'Fly a heading of 250 to intercept the localizer. Cleared ILS 29R circle to land 11L. Maintain 2;000 FT until established on the localizer.' No mention was given to intercepting the glideslope; or being established on the ILS. Conditions at that point were visual except for a small cloud between me and the airport. Upon intercepting the localizer (laterally); and being in visual conditions; my thinking was that I was cleared to descend at my discretion since no mention was made to intercepting the glideslope. I assumed that the Controller was aware I was in visual conditions; and I had always previously been cleared for an ILS approach with wording such as; 'Maintain 2;000 FT until intercepting glideslope'; or 'Maintain 2;000 FT until established on the ILS'. After a brief descent; Controller asked me to state my altitude; which at that time was 1;800 FT. He told me entry to the approach was at 2;000 FT. I affirmed back that I was correcting; and climbed back up to 2;000; at which point I was then a bit above the glideslope. This then caused a more rapid attempt to correct back to glideslope; with a brief overshoot; prompting a low altitude warning from the Controller. This was also rapidly corrected; at which point the Controller handed me over to Tower.Confusion arose due to the language of; 'Maintain 2;000 FT until established on the localizer'. While I know that I was cleared for the ILS; which means maintain the glideslope; during that process-intensive phase of flight; I just jumped to assume he meant established on the localizer to mean just that-laterally on the localizer (as the localizer provides no vertical guidance). A more precise phraseology; such as; 'Maintain 2;000 FT until established on the ILS'; or 'maintain 2;000 FT until established on the localizer and intercepting glideslope' would be more intuitive and prevent such erroneous thinking.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1193507
Time
Date	201408
Local Time Of Day	0601-1200
Place
Locale Reference	TOA.Airport
State Reference	CA
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	DA40 Diamond Star
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Private Flight Crew Sea
Experience	Flight Crew Last 90 Days 25 Flight Crew Total 568 Flight Crew Type 513
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

DA40 pilot reports being confused when cleared for the ILS and to maintain 2;000 ft until established in VMC and starts descending before glideslope intercept.