Date: 201502
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise; Parked
ATC / advisory: Center ZZZ
Aircraft component: Cockpit Door
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Other / Unknown
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Company Policy; Human Factors
Primary problem: Aircraft

Narrative: While at cruise; I indicated to the other crew members I needed to use the lavatory. The CA indicated he would go out as well. We followed procedures; CA went on oxygen; and I swapped places with the FA. After using the lavatory; the other FA called the cockpit; hung up; and I awaited the FA. When she went to open the door; it fell off the hinges and almost dropped straight out into the galley. I caught it; and after monkeying with it for about a minute; I managed to pop the top spring loaded hinge catch back into the hinge catch. We traded places; the CA went out. When it was time to come back in; the FA opened the door while I held onto the fabric strap to ensure the door would not fall out if it came loose again. It stayed in place.Upon landing in Airport ZZZ; we wrote the door up. Awaiting Maintenance; I discovered the top post catch was loose/broken; and any pressure on the top part of the door [would] cause the top hinge post to pop out. Contract Maintenance; under direction of Maintenance Control; reinstalled the door and was ready to OPS check 'OK' it. Before he did; I got in the cockpit and pushed on the top of the door; causing it to dislodge and caught it before it hit the floor.After several hours of the mechanic fiddling with it we timed out and went to the hotel. The next day; I communicated with the Captain who took our aircraft. He indicated that the door had not been properly repaired; and that the door once again came off in flight; resulting in a diversion to Airport ZZZ1.Maintenance Control needs to stop pushing Contract maintenance to sign off non-airworthy aircraft. Period. This is getting out of hand. Temporarily remedied broken cockpit door.

Callback: Reporter stated the ERJ-170-175 aircraft do have a history of cockpit door problems involving the older style door latch and door hinges. Three of their newer ERJ's also had similar door hinge problems during initial proving runs when they had received the aircraft. But in his report; the door latch was not the problem. The housing (catch) that held the door upper post had broken vertically; allowing the door post to pop out with little pressure and the door falling away into the Galley area.



Synopsis: A First Officer reports he was returning from a lavatory break when the cockpit door on an ERJ175 aircraft fell off its hinges and almost dropped straight out into the galley area as the door was opened. The housing (catch) that holds the door upper hinge post had broken vertically; allowing the door post to easily separate from the upper housing. Pressure on Contract Maintenance personnel to sign-off non-airworthy aircraft also noted by First Officer.