Date: 202112
Local time of day: 0601-1200
Location: LGB.Airport, CA
Flight conditions: Mixed
Weather elements / visibility: 3
Light: Daylight
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground LGB
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Human factors: Communication Breakdown; Workload; Situational Awareness; Troubleshooting; Confusion; Other / Unknown
Second reporter function: Captain; Pilot Flying
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown; Ground Incursion Taxiway
Detector: Person Air Traffic Control
When detected: Taxi
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Chart Or Publication; Environment - Non Weather Related; Human Factors; Weather; Airport
Primary problem: Ambiguous

Narrative: Flight delayed four hours. Taxied uneventfully to Runway 30. ATC cleared us across 26L approach on Taxiway L and then instructed us to hold short of the Runway 30 ILS critical area. We crossed the 26L approach area safely and uneventfully. Then we expected to see the standard 'train tracks' taxiway markings for the ILS critical area. Never saw the taxiway markings. It was not painted on Taxiway L. We both also never saw signage for the ILS critical area. Upon reference to the [airport diagram]; we discovered that no ILS critical area is depicted there either. Additionally; there is no reference to the critical area in the airport pages. Apparently; however; we accidentally crossed it. ATC advised us of our deviation and allowed us to continue taxi to Runway 30. We departed uneventfully. Also; LGB Ground did not advise in the ATIS that ILS 30 critical area was active. If they had done that; we could have used briefing and a shared mental model prior to taxi to investigate its location.Our company should verify where the ILS 30 critical area is on Taxiway L. If the airport is not marking it; we should advise pilots through the airport pages where to stop when they are told to hold short of the Runway 30 ILS critical area. The airport should certainly put it in the ATIS if it truly is not marked. This way; pilots can share a mental model of what to accurately expect on taxi.


Second narrative: LGB Ground's instructions were to taxi to Runway 30 and hold short of the 26L approach area. We briefly stopped when we were given additional instructions to cross the 26L approach area and hold short of the Runway 30 ILS critical area. I taxied very slowly due to limited visibility. Upon crossing the 26L approach on Taxiway Lima; I noticed ILS critical area signage. I briefly looked at my chart and determined it was for 26L since Runway 30 was approximately 2;000 feet away. Seconds passed; and I realized Runway 30 had a displaced threshold. I stopped the aircraft. Simultaneously the Ground Controller informed us we had passed the ILS critical area.Our company should verify where the ILS 30 critical area is on Taxiway L. If the airport is not marking it; we should advise pilots through our airport pages where to stop when they are told to hold short of the Runway 30 ILS critical area. The airport should certainly put it in the ATIS if it truly is not marked. This way; pilots can share a mental model of what to accurately expect on taxi.


Synopsis: Air Carrier flight crew reported a taxiway incursion by crossing into the ILS Critical area without clearance at LGB airport. The pilots reported there are no markings on the taxiway; no reference on ATIS and no reference to hold short lines on the airport diagram. In addition; the pilots reported LGB Ground did not inform them the critical area was active.