Date: 201808
Local time of day: 0601-1200
Location: ONT.Airport, CA
Flight conditions: VMC
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Taxi
ATC / advisory: Ground ONT
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Human factors: Communication Breakdown
Second reporter function: First Officer; Pilot Not Flying
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Took Evasive Action
Contributing factors: Human Factors; Procedure
Primary problem: Procedure

Narrative: Taxiing out to RWY 26R for departure at ONT. Ground clears us to cross RWY 26L and 26R on taxiway P and tells us there is traffic landing on 26L that is currently on an 8 mile final. There is traffic well ahead of us that is holding short of RWY 26R at the departure end waiting to depart; they are talking to Tower; we are still with Ground Control as instructed. We cross RWY 26L and as we approach RWY 26R; the First Officer (F/O) says that he thinks that the departing traffic that was previously holding short of RWY 26R is now taking off. We stopped short of RWY 26R on taxiway P; and held our position. The traffic on RWY 26R did depart. The F/O queried Ground to confirm that our clearance had indeed been to cross both RWY 26L and 26R on taxiway P; as it seemed odd to have been cleared to cross both runways if traffic was subsequently cleared for takeoff prior to us having cleared RWY 26R. Ground responded that yes; that was indeed our clearance; that we were correct and had been correctly executing that clearance; but that they had had traffic to depart. That seemed odd. Since we had held short of RWY 26R upon seeing the traffic depart in front of us; Ground then again cleared us to cross RWY 26R; turn right on November; and taxi to the departure end of taxiway N for departure. Based on the way the scenario unfolded; it appeared that we were given clearance to cross a RWY by Ground (RWY 26R) at the same time someone else was given clearance to depart on that same RWY (RWY 26R) by Tower. Regardless; by holding short of RWY 26R; no loss of separation occurred; but I am certainly questioning the validity of the given clearances by Ground and Tower to both us and the departing traffic. It appears that Ground gave us one clearance and Tower gave the other aircraft another clearance; both completely fine in and of themselves; but that they did not deconflict those two clearances with each other; and that those two clearances may have given us both access to RWY 26R at the same time; us to cross it; the other aircraft to depart on it. Had Ground switched us to Tower to cross RWY 26L and 26R and had Tower been controlling both aircraft; this conflict could have been avoided; that is probably the simplest way to have prevented this issue. Aside from that; had Ground and Tower simply communicated with each other more directly; this issue would also have been prevented. Above all of that though; in my mind; my F/O deserves accolades for speaking up as he saw what he correctly identified as a potential conflict so that we could avert that conflict by simply stopping; confirming our clearance; and not continuing until the conflict was resolved.


Second narrative: [Report narrative contained no additional information.]


Synopsis: Flight Crew of a large cargo transport reported a conflict during taxi with a departing aircraft on the crossing runway.