Date: 201908
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Cruise
Aircraft component: Toilet Furnishing
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: Other / Unknown
Human factors: Situational Awareness; Fatigue; Distraction; Time Pressure; Workload
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Dispatch
When detected: In-flight
Contributing factors: Company Policy; Equipment / Tooling; Human Factors; Staffing
Primary problem: Human Factors

Narrative: Aircraft X departed ZZZZ and shortly after reported that three of the 6 lavs on board had stopped working; all of the inop lavs were connected to the fwd waste tank. I was aware of this problem due to extensive history relating to the fwd waste tank sys. Again; the crew reported a lav system 2 control circuit breaker popped in the flight deck on the p11-6 panel. They agreed to continue and monitor the waste level of the operable tank.A few hours later; the crew reported that the forward tank was close to full and they were going to divert to have the operable lav tank serviced. ZZZZ1 was chosen as the diversion station. Maintenance at the station was notified by a coworker who assisted me because soon after; I was notified that Aircraft Y was now going to divert to ZZZZ2 due to fwd and aft lav tanks being full. I contacted ZZZZ2 local FBO and sent the MAA.At the time this was all happening; it was an exceptional busy day on the 767 and 757 desk; with a high out of service count for these fleets. I was also dealing with a field service in ZZZZ3; where we have many unforeseen problems with tooling; badging; etc. I was also dealing with an aircraft in ZZZ where numerous test flights had failed to confirm a flight deck noise. During this time of heavy phone calls and rollover calls from the 757 desk as well as the 767-400 desk having phone issues and was intermittently logged off throughout the day and working from another workstation; along with the fact that phone system between the 767-300;767-400 and the 757 desk has not been effective for the past 7 years (not a typo; 7 years!); despite numerous complaints. This causes all calls to roll to the 767-300 from the other desks but never to the 767-400 desk. On busy days; this further burdens the 767-300 and the 757 desk which are the busiest of the wide body desks.After both aircraft had reached their diversion stations; the tanks were serviced on both aircraft at both stations. The MEL was sent to the FBO mechanic to placard the forward waste tank per the MEL; in which he accomplished. Due to the transition from the scepter ELB (electronic logbook) and the Webtech ELB; all transactions can be done in Webtech except for the MAA/MAC transaction. This is a transaction not used too much on the wide body crew because mostly all wide body flights are from hub to hub and this transaction is used for vendors only. To accomplish this in the interim; transactions are actually done in triplicate on different screens. Both aircraft; at both diversion stations; were ready for a maintenance release at the same time. My coworker completed the MAC transaction for the items and I released the aircraft (aircraft). At the same time the flight crew from Aircraft X called looking for an MRD (maintenance release document) because they wanted to depart. The FBO mechanic then called me to tell me he had complied with the MEL and I could do the sign off in the ELB. When I went to do the transactions; I realized my coworker had not done the MAA transaction to the station. Again; the crew called looking for a maintenance release and had now departed off the gate in gander. I now had to send the MAA to obtain a work order and then complete the transactions in scepter ELB; a format not usually used on wide bodies. I assume in the busy environment; I inadvertently hit the 'clear' icon in the transaction and cleared the transaction; rather than place it on MEL. I contacted ZZZ when I got the chance to inform them about the inbound issue with the tank and to take the aircraft out of service. They called me back and asked me if the tank was on MEL because it did not show on the DIL (deferred item list). When I looked at the DIL; I realized I made the same mistake many mechanics make and call me in the attempt to correct. I am fully aware that I cannot create deferred items in flight; especially those that require dispatch authority. I decided I would correct the MEL once it got on theground in ZZZ. I also realized that the aircraft would arrive in ZZZ around the time our shift changes start. The two desks I work with go through turnover before my Relief arrives and so now the 767-300 desks take all the calls for the this and the -400 and 757's. Combined with the incredibly busy day and numerous out of service; I decided to start the deferral transaction in Webtech ELB to the point where all I had to do was enter it once the aircraft landed in ZZZ. Then; I would minimize the window so I would not forget to accomplish it before going home and relying on someone else to fix my mistake.Somewhere along the way; in all the chaos; I honestly don't know how; but the 'enter' button was hit on my deferral transaction. This created a deferral while the aircraft was in flight. I became aware of it when the dispatcher called me and said someone added a placard to an airborne flight. I looked and still don't know how; I realized my compounded mistake and told the dispatcher what had happened and I would file a TSAP (technician safety action program) at home that night. After work that night; I tried to access the company site to file the  TSAP on my home computer with no luck. After such a stressful day; I decided to try again the next day when my head was clearer. Again; I could not access the site. Tonight is my first night back at work where I am able to reach the TSAP site to file about the incident.First and foremost; fix the phone system on the 757-767-300-767-400 desks once and for all so the calls roll evenly and reduce the congestion. The 400 guy can't even pick up the calls to help out because the phones are set up incorrectly. They have been complained about so many times; people have given up. This is why no one wants to work this desk besides those currently on it who deal with it. Allow our Director the funding for a functioning phone system with the ability to handle the workload. This would never happen in a Dispatch environment and a Maintenance Control environment should be afforded the same or even greater standards. This issue of MAA/MAC transactions will be reduced once the transaction is incorporated into the Webtech ELB and the use of two ELBs and duplicate and triplicate transactions will not be required. This is imperative when time is critical with such short crew duty times that could cause flights being stopped and canceled in places like gander and ZZZZ1 which have incredible customer impact and unwanted media attention; which in turn puts unnecessary pressure on those trying to get to aircraft out safely and legally.




Synopsis: Maintenance Controller inadvertently assigned a deferral to an aircraft in flight.