Date: 201508
Local time of day: 1801-2400
Location: IND.Airport, IN
Flight conditions: VMC
Light: Night
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZID
ATC / advisory: Center ZID
Aircraft component: FMS/FMC
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Flying
Anomaly: ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Contributing factors: Human Factors; Procedure
Primary problem: Ambiguous

Narrative: We were in cruise at FL350. ATC gave us a crossing restriction to cross 70 miles east of RINTE at FL300. My FO dialed FL300 into the ASEL; verified that VNAV was selected and then entered the full restriction into the FMS. I verified that it was put in correctly and he activated it. The FMS didn't reject it; say over max descent angle; or display 'check PD Placement' like it normally would if the point was in an odd place. A couple minutes later ATC asked us about the restriction and if we had put 70 in for the distance. We had been getting ready for descent by looking at the SNKPT1 arrival; and I noticed then that we were only about 50 miles away from RINTE and the plane hadn't descended or alerted or anything. It had only been minutes since they assigned the restriction and there's no way we could have covered over twenty miles in that time but were really confused and I inquired them before they swapped frequencies about it. You could tell a supervisor took over comms; and told us the restriction was supposed to be 'something around 35 miles or so.' not the 70 that was originally given to us. He said not to worry about it and that everything was fine; but I figured it would be better to play it safe and file this report.I thought that I had seen the restriction up on the MFD but I can't be sure especially after ATC asked us about the mileage. But we definitely entered it into the FMS and ASEL correctly. I just think that we were either inside of the restriction already; or just on the edge of it and there was no way to make it. So it seems as though the M in CAMI was missed; at least partly. We were distracted with preparing for the descent but in the future I can use this experience to remind myself and other crew to keep an eye out for close or possible past restrictions.


Second narrative: While in cruise at FL350; when we received the crossing restriction of 'cross 70 miles east of RINTE at FL300.' Captain read back the clearance correctly as I set up for the restriction. The two of us adamantly verified the following: FL300 was set on our PFDs; RINTE/70/FL300 imputed into the flight plan and activated; along with verifying VNAV as active vertical guidance mode. Approximately 2 minutes later; ATC asked us to confirm the mileage of the previous issued crossing restriction. As Captain read back 70 miles east of RINTE; we realized we were well inside of 70 miles east of RINTE. ATC next transmission to us was in a different voice; 'just descend and maintain FL300.' The different voice I would assume was someone monitoring that frequency. Before leaving the frequency; Captain asked what the crossing restriction was supposed to be. ATC replied '30 miles East of RINTE at FL300.'Even though ATC had made a mistake of giving us the wrong mileage; I should have checked our current mileage from RINTE. I became complacent when the FMS accepted the crossing. Normally in that particular situation; the FMS would not allow a crossing restriction that it cannot meet. I believe fatigue was also an issue in the event. I was scheduled to finish a four day trip [in the late evening.] Due to delays [at departure airport]; I was not able to duty off until [the very early morning]. I feel I have not yet recovered from that as I had another day trip [the next day] as well. I did not feel fatigue until this flight as I had deadheaded to fly this leg back.


Synopsis: EMB170 flight crew is instructed to cross 70 NM east of RINTE on the SNKPT1 Arrival to IND at FL300 which is entered into the FMC. This crossing restriction is already behind the aircraft as ATC had meant to say 30 NM east at FL300. The crew is not aware of the problem until ATC questions the crew about the crossing restriction.