Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Critical
Air Traffic Control Issued New Clearance; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
Our aircraft had three MEL's when we arrived at the plane. One of which was a write up for Right Engine FADEC fault 1. The write up from the previous day was an R ENG DEGRADED caution message and was corrected with the R Engine FADEC fault 1 MEL that we had on our plane. The MEL book was consulted and we saw that we could dispatch so long as a Left Engine FADEC fault 1 was not present. We didn't have that; but we did have a Left Engine FADEC fault 2 status message that was also on MEL. The first part of the flight went off normally. Engine start; takeoff; and initial climb were all fine without any notable discrepancies. The problem began as we were climbing through FL240. I noticed the plane begin to make small; unusual movements and I noticed an odd sound; similar to when a pack cycles on and off in flight. As I looked up at the engine controls; I noticed that the left engine was at MCT thrust; while the right engine was at CLB thrust. Very quickly there afterward; the right engine instrument gauges (N1; ITT; N2) all disappeared and were replaced by yellow dashes. Accompanying these dashes were a few caution messages. The ones [I] remember were RUDDER LIMITER and APR CMD SET. It's possible that there were other messages that I did not see; particularly status messages. It was all happening very quickly and unexpectedly. Reacting to the messages I saw; I took control of the radios and instructed the First Officer to reference the QRH for APR CMD SET. As he began to do that; we received the master warning 'Engine Oil' and associated warning message. As well; the engine gauges came back but appeared as a windmilling engine might (N1 around 23; low ITT).I began to press the rudder to compensate for the change in yaw motion and to bring the brick back to center. I informed ATC that we had lost our right engine and that we needed a descent back to FL240; since by this time we were at about FL245. He immediately gave it to us and told us to advise him what we wanted to do.While all of this was happening; about 30-45 seconds after the engine initially went out; it began to come alive again and very quickly all of the messages went out; expect APR CMD SET; which stayed for another 30 seconds after the engine relit itself. We advised ATC that we needed to return to [the airport] immediately. We were approximately 75 miles west of the airport at the time of the incident and we received vectors direct to the airport. While we turned back and began to head to the field; I gave control of the radios back to the first officer and advised the flight attendants of what was going on and told them that; at that time; I didn't have any special instructions for them. I also sent an ACARS message to the company to tell them what we were doing. The first officer; meanwhile; picked up the ATIS and got all the appropriate landing data. We briefed the approach we were expecting and ran the 'In Range Checklist.'The approach itself and the landing were normal. After we landed; I spoke with the dispatcher and a maintenance controller and told him all the details of what happened. I was informed that the issue was most likely a bad FACDEC and that they would have to fly in a new FADEC to fix the engine.As far as I am aware; during the whole event; all standard operating procedures were adhered to and at no point were any clearances deviated from. The only suggestion that comes to mind would be for maintenance not to dispatch with both FADEC's having faults; since our L Engine FADEC also was on MEL for a FADEC 2 fault. The write up from the previous day was an R ENG DEGRADED caution message and was corrected with the R Engine FADEC fault 1 MEL that we had on our plane. I would suggest some sort of check of the FADEC after a DEGRADED message instead of an MEL fix for 10 days.
The reporter stated that the aircraft had two MEL items that were very similar but were legal per the FOM to dispatch with this condition. The reporter stated that both MEL items were for the Full Authority Digital Engine Control; (FADEC). The reporter stated that the Right-hand (RH) engine had a FADEC channel 2 fault and the Left-Hand engine had a FADEC 1 fault. The reporter also stated that with each FADEC having only two channels; and each FADEC having one channel deferred; that leaves you with half of your redundancy. The reporter asked if the working channel on a FADEC fails; does the other FADEC have the ability to operate both engines using only one channel? The reporter also stated that perhaps this type of deferral should be looked into to ensure this issue doesn't occur again. The reporter stated that they also got a 'Rudder Limiter' fault due to the asymmetrical thrust because of the loss of the RH engine.
[Report narrative contained no additional information.]
Bombardier CRJ flight crew reported that during climb the plane began to make small unusual movements the right engine instrument gauges (N1; ITT; N2) all disappeared and were replaced by yellow dashes.