Date: 202108
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Dusk
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class D ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: PFD
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Situational Awareness; Workload; Distraction
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Procedure

Narrative: After combining the STAR waypoint onto the RNAV waypoint in the FMS; we re-entered the altitude due to the FMS EPIC load 27.3 known issues of 'melding' altitudes. We just re-entered the altitude in the FMS on the fix which acted as a 'vertical direct to' and deleted all of the crossing restrictions between our current altitude and the set altitude. This removal of all the crossing restrictions went unnoticed.We noticed the terrain below us. We could still see it and thought it seemed a 'little close.' We both had our terrain pages up and I noticed the highest terrain was 11;700 ft. and we were still at 14;800 ft. This error continued unnoticed as our attention turned towards a diverting aircraft from a nearby airport to our destination due to weather. Our approach would take us close to that airport; so I instructed the FO (First Officer) to keep terrain up on his side and I would take a look at the radar on mine. After a few minutes of looking at the weather; we determined that it was not a threat. About that time; we received a 'low altitude' call from the very busy ZZZ Approach Controller. We immediately leveled off; even though we still had the terrain in sight. We discovered the error; re-entered the remaining crossing restrictions; and continued. The remainder of the flight continued without incident. We never received any GPWS alerts.I mis-applied the 'Action Required' from our Flight Operations Bulletin. We should have deleted the 'melded' altitude and then re-entered the correct one. Instead; I just re-entered the crossing altitude and did not re-verify the crossing restrictions. Since we both had verified all the altitudes prior to the descent checklist; it gave us the confidence that they would still be there.While I take full responsibility; the FMS 'issues' are just waiting there for a slightly distracted crew; with weather. We would have had no issue; if I complied with the actions in the Flight Operations Bulletin; but there are a lot of them to keep track of that are not observed on a daily basis.


Second narrative: On a flight from ZZZ to ZZZ1; on ZZZZZ Arrival into ZZZ1 with planned RNAV RNP Y XXL. Cleared direct ZZZZZ1 and descend via ZZZZZ. Approximately at ZZZZZ2 the Approach Controller issued clearance for the RNAV Y XXL. The Captain; PM; connected ZZZ1 from the approach to ZZZ1 on the arrival. Because of the Flight Operations Bulletin about altitude melding; the Captain selected 9000 ft. and re-entered it. The FO (First Officer); PF; confirmed it. The aircraft entered a shallow; steady descent to 9000 ft. at ZZZ1. The conditions were VMC and both pilots saw the terrain. There was a large thunderstorm near ZZZ2 VOR. The Captain was adjusting the radar when ATC issued a low altitude alert between ZZZZZ3 and ZZZZZ4. The Captain had the FO level off the aircraft at 12;000 feet. The Captain re-entered the correct altitude at ZZZZZ4. The rest of the approach went without further incident. We never received a GPWS warning.I checked all the altitudes on the arrival and trusted they were correct in the FMS. I was mostly concerned about the aircraft making the crossing restriction at ZZZ1 at 9;000 feet. where we melded fixes. When the Captain and I confirmed / activated the 9000 ft. in the MCDU; I didn't realize that we accidentally just created a 'vertical direct to' and deleted all altitudes between ZZZZZ2 and ZZZ1. So when we flew over ZZZZZ5 and ZZZZZ4; there were no altitudes next to the fixes on the flight plan page. [I suggest that] on a STAR after crossing every fix; have the PF read off the chart 'next fix; ZZZZZ5; 16;000 feet.'


Synopsis: EMB-175 flight crew reported inadvertently deleting all crossing restrictions on the approach and descended below minimum altitude.