Narrative:

After a 5 hour maintenance delay, I again called for taxi clearance at about XG00 local. 5 hours previous, during the first call to taxi, we were cleared to taxi to runway 25R, hold short of runway 25L. Runway 25L was not active. With this second call to taxi, I understood the instructions to be the same. Taxi to runway 25R, hold short of runway 25L at 8 (meaning taxiway 8). We taxied up to runway 25L, held short of the runway on taxiway 8. The ground controller asked if we had made the turn onto taxiway 8. I said that we did because our taxi instructions said runway 25R, hold short of runway 25L. (At this point we had not crossed any runways, active or inactive.) the ground controller then said that by taxiing on taxiway 8, we had crossed into the ILS critical area of runway 25L. During our 5 hour delay, runway 25L had become active with arrs. We were starting our trip at lax, did not copy the arrival ATIS, and the departure ATIS only lists the departure runways. We also stated that there were no yellow and black united states airport signs painted on any concrete taxiway defining the ILS critical area, nor were there any red and white united states airport signs marking the ILS critical area. The ground controller then stated that our taxi clearance was to runway 25R, hold short of runway 25L and taxiway 8. I understood taxi to runway 25R, hold short of runway 25L at taxiway 8. (A difference of 'and' or 'at'.) the difference between the words 'and' and 'at' can be confusing at XG00 when our wakeup call was at XA00. Controling traffic at XG00 can be tiring when a person has probably also been working all night. No aircraft movement was disrupted during our taxi onto a taxiway, we held there. The controller did have to state to 2 arriving aircraft that the ILS critical area had an aircraft in the area, and we proceeded normally to the departure runway 25R. Lessons: listen up to taxi instructions. Where are the yellow painted airport signs? Where are the red/white airport signs? Should not the ATIS mention when critical areas are active? Should not departure ATIS mention the arrival runways? Should not the 10-9 pages in the manual show critical areas on the airport diagram. I know, after 22 yrs of flying, it is an art, more difficult, I assume than brain surgery. Callback conversation with reporter revealed the following: there are no signs indicating that an ILS critical area exists at the east end of the runways. This per a callback to the reporter who added that they taxied from the southeast cargo area north on taxiway 4, west on taxiway F and north on taxiway 8 and held short of runway 25L. In a callback to an ATCT controller, analyst was told that there is also an 'obstacle critical area' that is to be kept clear during CAT ii approachs. Aircraft on taxiway F are clear but as soon as they turn north on taxiway 8, they are in this area. He said the only way a pilot would know this is for the controller to explicitly instruct the pilot to hold short of taxiway 8.

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Original NASA ASRS Text

Title: CARGO WDB CREW ACCUSED OF IMPINGING ON AN 'OBSTACLE CRITICAL AREA.'

Narrative: AFTER A 5 HR MAINT DELAY, I AGAIN CALLED FOR TAXI CLRNC AT ABOUT XG00 LCL. 5 HRS PREVIOUS, DURING THE FIRST CALL TO TAXI, WE WERE CLRED TO TAXI TO RWY 25R, HOLD SHORT OF RWY 25L. RWY 25L WAS NOT ACTIVE. WITH THIS SECOND CALL TO TAXI, I UNDERSTOOD THE INSTRUCTIONS TO BE THE SAME. TAXI TO RWY 25R, HOLD SHORT OF RWY 25L AT 8 (MEANING TXWY 8). WE TAXIED UP TO RWY 25L, HELD SHORT OF THE RWY ON TXWY 8. THE GND CTLR ASKED IF WE HAD MADE THE TURN ONTO TXWY 8. I SAID THAT WE DID BECAUSE OUR TAXI INSTRUCTIONS SAID RWY 25R, HOLD SHORT OF RWY 25L. (AT THIS POINT WE HAD NOT CROSSED ANY RWYS, ACTIVE OR INACTIVE.) THE GND CTLR THEN SAID THAT BY TAXIING ON TXWY 8, WE HAD CROSSED INTO THE ILS CRITICAL AREA OF RWY 25L. DURING OUR 5 HR DELAY, RWY 25L HAD BECOME ACTIVE WITH ARRS. WE WERE STARTING OUR TRIP AT LAX, DID NOT COPY THE ARR ATIS, AND THE DEP ATIS ONLY LISTS THE DEP RWYS. WE ALSO STATED THAT THERE WERE NO YELLOW AND BLACK UNITED STATES ARPT SIGNS PAINTED ON ANY CONCRETE TXWY DEFINING THE ILS CRITICAL AREA, NOR WERE THERE ANY RED AND WHITE UNITED STATES ARPT SIGNS MARKING THE ILS CRITICAL AREA. THE GND CTLR THEN STATED THAT OUR TAXI CLRNC WAS TO RWY 25R, HOLD SHORT OF RWY 25L AND TXWY 8. I UNDERSTOOD TAXI TO RWY 25R, HOLD SHORT OF RWY 25L AT TXWY 8. (A DIFFERENCE OF 'AND' OR 'AT'.) THE DIFFERENCE BTWN THE WORDS 'AND' AND 'AT' CAN BE CONFUSING AT XG00 WHEN OUR WAKEUP CALL WAS AT XA00. CTLING TFC AT XG00 CAN BE TIRING WHEN A PERSON HAS PROBABLY ALSO BEEN WORKING ALL NIGHT. NO ACFT MOVEMENT WAS DISRUPTED DURING OUR TAXI ONTO A TXWY, WE HELD THERE. THE CTLR DID HAVE TO STATE TO 2 ARRIVING ACFT THAT THE ILS CRITICAL AREA HAD AN ACFT IN THE AREA, AND WE PROCEEDED NORMALLY TO THE DEP RWY 25R. LESSONS: LISTEN UP TO TAXI INSTRUCTIONS. WHERE ARE THE YELLOW PAINTED ARPT SIGNS? WHERE ARE THE RED/WHITE ARPT SIGNS? SHOULD NOT THE ATIS MENTION WHEN CRITICAL AREAS ARE ACTIVE? SHOULD NOT DEP ATIS MENTION THE ARR RWYS? SHOULD NOT THE 10-9 PAGES IN THE MANUAL SHOW CRITICAL AREAS ON THE ARPT DIAGRAM. I KNOW, AFTER 22 YRS OF FLYING, IT IS AN ART, MORE DIFFICULT, I ASSUME THAN BRAIN SURGERY. CALLBACK CONVERSATION WITH REPORTER REVEALED THE FOLLOWING: THERE ARE NO SIGNS INDICATING THAT AN ILS CRITICAL AREA EXISTS AT THE E END OF THE RWYS. THIS PER A CALLBACK TO THE RPTR WHO ADDED THAT THEY TAXIED FROM THE SE CARGO AREA N ON TXWY 4, W ON TXWY F AND N ON TXWY 8 AND HELD SHORT OF RWY 25L. IN A CALLBACK TO AN ATCT CTLR, ANALYST WAS TOLD THAT THERE IS ALSO AN 'OBSTACLE CRITICAL AREA' THAT IS TO BE KEPT CLR DURING CAT II APCHS. ACFT ON TXWY F ARE CLR BUT AS SOON AS THEY TURN N ON TXWY 8, THEY ARE IN THIS AREA. HE SAID THE ONLY WAY A PLT WOULD KNOW THIS IS FOR THE CTLR TO EXPLICITLY INSTRUCT THE PLT TO HOLD SHORT OF TXWY 8.

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.