Created Sunday, Jun 28th 2026 15:26Z, last updated Sunday, Jun 28th 2026 15:26Z
An American Airlines Airbus A321-200, registration N104NN performing flight
AA-2453 from Los Angeles,CA to Boston,MA (USA), was taxiing for departure, when both engines rolled down, stabilized and then failed. The aircraft returned to the stand.
A replacement Airbus A321-200 registration N110AN reached Boston with a delay of about 7.5 hours.
On Jun 27th 2026 The Aviation Herald received information about this occurrence in form of the text of an investigation report. The source also told The Aviation Herald: "The other information that I have is that AAL quickly discarded and threw away the switches, an unbelievable decision considering what could have been learned from this failure. I don't know why they did that but this is clearly not good for safety... To my knowledge the root cause is still unknown and there is unfortunately no Annex 13."
The investigation concluded the root cause of the occurrence was:
The Engine M/L switch controls the HPSOV, the LPSOV and the reset of the EEC. The status of the M/L is also sent to the FWCs through the EIU for E/Ws computation purposes.
Based on the Flight Data provided by AAL, both engines' M/L signals were seen transiently in the OFF position during 1 second at different times leading to HPSOV closure and EEC channel in control change.
The root cause of this event is a non-simultaneous intermittent signal flickering (during 1 second) from both engines' M/L switch during taxi out (phase 2), when A/C was in static. Note that the engines' master switches are independent.
The report reads in whole
Event/Finding Description:
American Airlines A321 MSN 05895 Return to Stand on 18-Feb-2026.
During taxi-out of flight AA2453 from Los Angeles (LAX) to Boston (BOS), both engines experienced engine roll back, then stabilized, and then failed.
ENG 2 FAIL and ENG 1 SHUT DOWN triggered on ECAM.
-------------------- Short Term Action:
After review of the DFDR, per the TSM tasks 73-00-00-810-855-A and -856-A, maintenance changed both engine master switches 2KC/3KC.
Each engine was started 4-times and allowed it to run for 5-minutes after each successful start. Engines operated normally after each start, thus airplane returned to service.
IAE advised AAL to replace the EEC2.
-------------------- Analysis/Follow-up:
-------------------- Additional information
Aircraft (A/C) Model: 321-231; MSN: 05895; Registration: N104NN; Operator: American Airlines (AAL)
Engine Position: #1, #2
Engine Type: V2533-A5
Engine 1 Serial Number (ESN 1): V18178
Engine 1 Time/Cycle Since New (ETSN/ECSN 1): 28922 Flight Hours (FH) / 10673 Flight Cycles (FC)
Engine 1 Time/Cycle Since Repair (ETSR/ECSR 1): 3920 FH / 750 FC
ESN 2: V11133
ETSN/ECSN 2: 80048 FH / 27075 FC
ETSR/ECSR 2: 14617 FH / 2819 FC
Event description
On the 19th of February 2026 MSN 05895 experienced both engines roll back below idle at different times during taxi-out of flight from Los Angeles airport (LAX) to Boston airport (BOS) along with "ENG 1 SHUT DOWN" and "ENG 2 FAIL" ECAM Warnings (E/W). The pilots reported both engines roll-back, then stabilized, and then failed during this event. The aircraft returned to the stand for troubleshootings.
-------------------- Post Flight Report (PFR) analysis
The following E/Ws were recorded in the PFR in the Flight Phase (FP) 2 at 05:59 UTC:
"ENG 1 SHUT DOWN" E/W: This alert triggers when engine 1 master is at OFF in phases 3 to 8 or when engine 1 FIRE push button is pushed in phases 1, 2, 9 and 10.
"ENG 2 FAIL" E/W: This alert triggers when the engine 2 core speed is below idle, with the ENG MASTER lever set to ON, and ENG FIRE push button not pushed.
-------------------- Flight Data analysis:
The Flight Data shows the following sequence:
At 05:53:03 - engine 1 Master Lever (M/L1) was set to ON to start engine 1.
At 05:54:10 - engine 1 started and stabilized at idle.
At 05:54:22 - M/L2 was set to ON to start engine 2.
At 05:54:24 - M/L1 was recorded in OFF position for 1 second. The High Pressure Shutoff Valve (HPSOV) and Low Pressure Shutoff Valve (LPSOV) were closed transiently. All engine 1 parameters rolled back along with an Electronic Engine Controller (EEC) 1 channel in control change from Channel B to channel A. Engine 1 N2 dropped from 61% to 46 %.
At 05:54:38 - engine 1 recovered and stabilized again at idle (61% N2).
At 05:55:28 - engine 2 started and stabilized at idle.
At 05:56:03 - M/L1 was recorded in OFF position for 1 second. The HPSOV1 was closed transiently. All engine 1 parameters rolled back along with an EEC 1 channel in control change from Channel A to channel B. Engine 1 N2 dropped from 58.5% to 47 %.
At 05:56:29 - engine 1 recovered and stabilized again at idle (58.4% N2), engine 2 was at 58.4% N2.
At 05:59:11 - M/L1 was set to OFF, engine 1 parameters decreased.
At 05:59:14 - M/L2 was recorded in OFF position for 1 second. The HPSOV2 were closed transiently. All engine 2 parameters rolled back. EEC 2 channel in control changed also transiently from channel A to channel B and then back to channel A. Engine 2 N2 dropped from 58.8% to 47%.
At 05:59:28 - engine 2 recovered and stabilized again at idle (60% N2).
At 05:59:35 - engine 2 throttle lever was advanced to 7°. All engine 2 parameters increased accordingly.
At 06:00:41 - The HPSOV2 was closed transiently. All engine 2 parameters rolled back. EEC 2 channel in control changed from channel A to channel B. Engine 2 N2 dropped from 73% to 55 %.
At 06:02:30 - M/L 2 was set OFF.
Note that the Flight Data are recorded at a sample of 1 pps. Transient parameters change could be not recorded on the data if it lasts less than 1 second.
-------------------- Troubleshooting:
After the event, the operator reported that the maintenance team performed the Troubleshooting Manual (TSM) tasks 73-00-00-810-855-A "Engine 1 Less Than Idle" and 73-00-00-810-856-A "Engine 2 Less Than Idle" leading to the replacement of both engine master switches 2KC and 3KC.
Engine 1 Master switch details:
Part Number (P/N): E0499B4AA0B02A
Engine 2 Master switch details:
P/N: E0499B4AA0B03A
Then each engine was started 4 times and allowed it to run for 5-minutes after each successful start. Engines operated normally after each start.
The maintenance team also replaced the fuel filter of both engines without finding reported.
Further inspection of the previous legs reports from EEC 2 channel B showed an " EEC2 " fault message which indicates an EEC2 internal failure recorded on the 09th, the 13th and the 17th of February 2026. This fault message was associated with the fault code " EMWVF " which indicates a channel B memory write verification failed. The engine manufacturer (IAE) also reviewed the data and advised AAL to replace the EEC2. The EEC 2 was replaced and sent to Collins for investigation.
EEC 2 details:
P/N: 824972-7-026
S/N: 2540-0060
Software : SCN23
The Aircraft returned to service without further issue reported since.
-------------------- Root cause analysis:
The Engine M/L switch controls the HPSOV, the LPSOV and the reset of the EEC. The status of the M/L is also sent to the FWCs through the EIU for E/Ws computation purposes.
Based on the Flight Data provided by AAL, both engines' M/L signals were seen transiently in the OFF position during 1 second at different times leading to HPSOV closure and EEC channel in control change.
The root cause of this event is a non-simultaneous intermittent signal flickering (during 1 second) from both engines' M/L switch during taxi out (phase 2), when A/C was in static. Note that the engines' master switches are independent.
-------------------- Corrective Actions:
Short Term Action:
After review of the DFDR, per the TSM tasks 73-00-00-810-855-A and -856-A, maintenance changed both engine master switches 2KC/3KC.
Each engine was started 4-times and allowed it to run for 5-minutes after each successful start. Engines operated normally after each start, thus airplane returned to service.
IAE advised AAL to replace the EEC2.
Related Flight:
AA2453,
American Airlines News
