An Automation Confusion Accident?
Timeline of the Jan. 3, 2004, crash of a Flash Airlines Boeing 737-300
02:41:59 -- Take off initiated with standard call outs.
02:42:02 -- TOGA (take off go around) mode engaged, then disengaged at 02:42:04 (old style 737 Classic computer?)
Aileron movements during T/O roll and lift-off were consistent with crosswind.
02:42:43 -- As the airplane was climbing through 440 feet the captain requested Heading Select. The first officer (F/O) confirmed the command and the flight data recorder (FDR) records that Heading Select mode was engaged.
02:42:48 -- Captain requests "Level Change."
02:42:49 -- The F/O announces, "Level Change, MCP speed, N1 armed, Sir."
02:42:59 -- the F/O announces "one thousand." At the same time, ATC reports the departure time and confirmed left turn clearance. The F/O acknowledges the clearance. This was the last ATC transmission from the flight crew. The aircraft rolled to 20? left bank and began a climbing turn. The turn continued as the magnetic heading approached 140? (at an altitude of 3600 feet), at which point the bank angle decreased to approximately 5? left bank.
02:43:19 -- EgyptAir Flight (MSR 227), a flight from Hurgada inbound to Sharm el-Sheikh, called ATC. Conversations between ATC and MSR 227 continue for approximately 60 seconds.
02:43:37 -- The captain calls for the After Takeoff checklist. There was no audible response from the F/O.
02:43:55 -- the Captain calls "Autopilot." There was no immediate response from the F/O or mode changes recorded on the FDR (likely due to callsign MSR and ATC transmissions)
Timeline: 02:43:58 --Captain states, "Not yet."
ASW comment: i.e., "Don't engage autopilot until I've rolled wings level"?
Timeline: 02:43:59 -- FDR records the autopilot engaged, and that the roll mode transitioned to CWS-R mode. This transition would have resulted in loss of Heading Select Mode.
ASW comment: F/O misunderstands and engages autopilot (A/P) anyway (1 sec later). Major implications ensue ... on a very black night, over the Red Sea.
Timeline: 02:44:00 -- F/O states, "Autopilot in command, sir."
02:44:01 -- Captain states "EDEELO," (an Arabic exclamation expressing a sharp response of some kind).
At the same time, the FDR records momentary movements of aileron surfaces. The right aileron deflects to 7.2 degree TEU for one second.
ASW comment: A result of A/P being engaged while rolling (ailerons and even spoilers deflected) is that it then "kicks" and induces a disconnect due to no synchronization with the aileron servo-actuators. In addition the left outboard (#1) slat was faulty and may have remained extended, inducing a minor rolling moment to the right (not a major malfunction).
Timeline: 02:44:02 -- Cockpit voice recorder (CVR) records the A/P disconnect warning and the FDR recorded the A/P disengaged. The aural warning lasted for 2.136 seconds.
ASW comment: But the pilot (busy exclaiming) evidently fails to register what it was conveying and reflexively cancels the autopilot warbler -- then forgets about it (outta sight or outta hearing = outta mind).
During this time, an increase in pitch and decay in airspeed were observed.
ASW comment: Crew is unaware that neither pilot nor autopilot is now in control... aircraft is flying itself.
Timeline: 02:44:05 -- Captain requests Heading Select mode.
ASW comment: i.e. the Pilot still assumes that autopilot is engaged and has control.
Timeline: 02:44:07 -- F/O states "heading select" and the FDR records Heading Select mode engaging. This mode transition would have resulted in the reappearance of the flight director roll command bar (for direct pilot guidance). During this sequence, the aircraft's left-bank continued to decrease at a slow rate until the airplane was briefly wings level. Beginning at this time, the FDR records a series of aileron motions that command a CWS right bank and subsequent right turn.
ASW comment: Less than a minute now to impact. F/O positive response tends to confirm A/P is doing its duty (even though the F/O has only "hit" the Heading Select button).
Pilot thinks that his yoke input is using CWS-R and that the aircraft will roll out on its selected HDG.
Consequently the Pilot is making only the necessary CWS roll initiation inputs to the yoke.
Timeline: 02:44:18 -- Captain says, "See what the aircraft did?"
At this point the aircraft bank angle was about 12 degrees to the right. (extended #1 slat may have been inducing a right roll).
ASW comment: Aircraft has gone through the ordained heading without rolling out. Captain is now confused, solidly convinced that the autopilot is still engaged and that he's using CWS-R -- (or rather, thinks that he is).
Timeline: 02:44:27 -- F/O states, "Turning right, sir." Three seconds later, the captain responds, "What?" At the same time, his bank angle is 17 degrees to the right and the FDR records that his aileron motions are to increase the right bank.
ASW comment: Confusion by pilot between displayed bank directions (left for right) and rolls further right? Are the command bars obscuring his interpretations of aircraft roll attitude or is he more likely confusing Western and Soviet-style artificial horizon (AH) displays?
Timeline: 02:44:31 -- F/O states, "Aircraft is turning right." One second later, the captain responds, "Ah." Timeline: 02:44:35 -- Captain states, "Turning right." At this point, the bank angle was 23.6 degrees to the right.
ASW comment: F/O attempts to keep the captain informed. A misreading of a 30 degree banked right display for a 30 degrees left? Has the captain reverted to "seeing" his MIG 21's AH presentation?
Timeline: 02:44:37 -- Captain states, "How turning right?" Bank angle was 29.7 degrees. (i.e., "How come it's turning right?" Puzzlement.)
ASW comment: Up to this point, pilot is possibly using either CWS (i.e. his yoke) or the inoperative A/P turn controller to counter the adverse turn, or is misreading the electronic attitude display indicator's (EADI) bank presentation and confusing it with a MIG 21's.
Timeline: 02:44:41 --Captain states, "OK, come out." At this point, the bank angle was slightly more than 40 degrees right bank and the FDR records the ailerons returning to just beyond neutral, the high roll-rate to the right stopped and a momentary left roll-rate occurred resulting in a slight decrease in the right bank from 43 degrees to 42 degrees before additional aileron movements command an increase in the right bank.
ASW comment: 25 seconds to impact. Pilot confusion evident, he's attempting to get the CWS back within 30 degrees AoB, for to enable its CWS-R ability to auto-roll out on the heading bug, but he's misreading the EADI's depiction of bank attitude, possibly because of the presence of the FD command bars, but equally plausibly, because he's seeing it as a MIG21 attitude instrument display.
Timeline: 02:44:41.5 -- F/O states, "Overbank."
The bank angle at this time was just beyond 50 degrees right bank. The airplane reaches its maximum altitude of just over 5460 feet.
Timeline: 02:44:41.7 -- Captain states, "Autopilot." He repeats the statement at 02:44:43.4.
ASW comment: Pilot is disoriented; a situation perhaps compounded by the FD command bars or reversion to interpreting a Soviet-style AH display.
He now suspects the autopilot is at fault or disconnected and wants his autopilot re-engaged/reset, but it's now way outside its engagement limits anyway.
Timeline: 02:44:44 -- F/O states, "Autopilot in command."
No A/P engagement was recorded on the FDR. The bank angle was approaching 60 degrees right bank. Pitch angle was zero and altitude was 5390 feet.
ASW comment: Only a reassurance by the F/O. He himself still believes that the A/P remains engaged. An F/O cannot visually discern any difference between manual control and use of CWS-R via the yoke. But this unhelpful reassurance serves to further mislead the captain.
Timeline: 02:44:46 -- Captain again states, "Autopilot."
ASW comment: Pilot still wants autopilot engaged because he feels that he's "lost the plot." The situation now turns critical as aircraft attitude quickly goes extreme.
Timeline: 02:44:48 -- F/O states, "Overbank, Overbank, Overbank."
The bank angle was passing through 70 degrees right bank, pitch angle was 3 degrees nose down and altitude was 5330 feet. Two seconds later, the captain responds, "OK."
ASW comment: The aircraft's nose is falling naturally due to overbank. CRM dictates that an F/O should now assume disorientation and take control, but this F/O also believes A/P is in control and is quite undecided. He's naturally reassured by the captain's throwaway acknowledgement of "OK." (Note the perils of mutual reassurance).
The FDR continues to record aileron motions that increase the right bank.
ASW comment: Pilot is disoriented, misreading the unusual beyond-his-experience EADI presentation and rolling the wrong way. Per the CrossAir SAAB 340, you don't get to make that mistake even once, and get away with it ... not in this scenario. Situation is now irretrievable.
Timeline: 02:44:52.8 -- F/O again states, "Overbank."
Bank angle was approaching 90 degrees, pitch attitude was 23 degrees nose down, and the altitude was 4860 feet.
Timeline: 02:44:53.4 --Captain responds, "OK, come out." The FDR records aileron motions to increase the right bank.
ASW comment: Pilot continues to roll the wrong way, i.e. towards the inverted
Timeline: 02:44:56 --F/O states, "No autopilot commander."
Bank angle was 102 degrees, pitch attitude was 37 degrees nose down, and the altitude was 4100 feet.
ASW comment: F/O has perhaps been trying to engage the A/P, but it's outside its engagement parameters OR maybe he's just had a dawning realization (or confirmed via its annunciators) that the A/P is OFF.
Timeline: 02:44:58 -- Captain states, "Autopilot."
At the same time the FDR records a large aileron motion to the left and the airplane begins rolling back toward wings level. The maximum bank angle recorded was 111 degrees right.
Pitch attitude at the time was 43 degrees nose down and altitude was 3470 feet.
ASW comment: Captain is confused by the EADI display and still sees the autopilot as being either his salvation (or the cause). However his recovery actions are via the yoke and now in the correct sense. He has recognized the unusual attitude and started a positive recovery, although too late to affect the outcome (8 seconds from impact).
Timeline: 02:44:58.8 -- The observer states, "Retard power, retard power, retard power."
Timeline: 02:45.01.5 -- Captain states "Retard power," and the FDR records both engine throttles being moved to idle. The bank angle was 51 degrees right bank, pitch attitude was 40 degrees nose down and altitude was 2470 feet. Timeline: 02:45:02.0 -- The CVR records the sound of the overspeed warning. The FDR records the airspeed as 360 KIAS (knots indicated airspeed). Recovery from severe right bank and nose down pitch continues.
Timeline: 02:45:04.3 -- Captain states, "Come out."
Bank angle is 14 degrees right, pitch attitude is 31 degrees nose down, altitude is 760 ft, and airspeed is 407 KIAS.
ASW comment: Unrecoverable parameters; insufficient height available. Note how fast loss of control can occur.
Timeline: 02:45:05 -- The CVR records a sound similar to ground proximity warning. Aircraft impacts the water at 02:45:06 with: Bank Angle 24.6deg to the right; Pitch Angle 24deg Nose down; Vertical G. Load 3.9g / AoA 5.46deg; Speed 416 Kts / HDG 316deg