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27 December 1991 - SAS 751

The MD-81 arrived from Zurich at 22.09h and was parked at gate 2 overnight with temperatures of around +1 deg. C. Approx. 2550kg of fuel remained in each wing tank. The aircraft was scheduled to leave Stockholm for Copenhagen at 08.30h and the temperature had dropped to -0 deg C in the early morning.

During the night and in the early morning clear ice had formed on the upper side of the wings, but this was not detected by the ground crew member who checked the forward part of the wing. The aircraft was fuelled with 1400kg of fuel and was ready for de-icing at 08.30h, which was done using 850l of Type I fluid. After de-icing the mechanic didn't check whether there was any clear ice on the upper side of the wings, since he had previously found none.

The flight was then cleared to taxi to runway 08 and the aircraft took off at 08.47h. After 25 seconds (at 1124ft height) bangs, vibrations and jerks were perceived in the aircraft. This was caused by a no.2 engine surge. The engine was throttled down a little, but throttle control simultaneously changed to an automatic mode which increased throttle setting with altitude (Automatic Thrust Restoration - ATR). This in turn increased the intensity of the surging. The no.1 engine surged 39 seconds later, but this was not noticed by the flight crew. An attempt to switch on the autopilot at 2616ft failed. At 76 resp. 78 seconds into the flight both the no.2 and no.1 engine failed after breakup of the stage 1 stators of both engines (initiated by high loads from the surges). The aircraft was climbing through 3206ft at that moment with a 196 KIAS. A no.1 engine fire warning at 91 seconds into the flight made the crew activate the fire extinguishing system.

A SAS captain traveling the passenger cabin realized that there were problems and hurried to the cockpit to assist the flight crew. The aircraft was in a gliding left turn at that moment. When descending through 420m, still in the clouds, the assisting captain gradually extended the flaps. The flaps were fully extended at 1100ft (340m) and the plane broke through the clouds at 980-820ft. A field in the direction of flight was chosen for an emergency landing. The wheels were selected down and Stockholm control was informed about the imminent crash-landing. The MD-81 contacted trees at 121kts and a major portion of the right wing broke off. The plane then struck sloping ground tail-first and slid along the ground for 110m. The fuselage was broken into three pieces, but there was no fire.

25 People were injured, two of them seriously. Nobody died in the accident, which is known in Sweden as Gottrörakraschen (the Gottröra crash). One of the reasons for the lack of deaths was the brace position that was instructed by flight attendants.

The flight crew received praise for the skilled emergency landing in a potentially fatal situation.


Transcript of the Cockpit Voice Recorder (CVR)

FC = Captain
FO = First Officer
FC2 = Captain coming into cockpit to assist during flight
CA1 = Cabin attendant no.1 / purser
CA2 = Cabin attendant no.2
CA3 = Cabin attendant no.3
CA4 = Cabin attendant no.4
TWR = Arlanda Tower
DEP = Stockholm Control
[] = interpreted information or additional information about the content
() = uncertain
?? = not interpreted due to disturbance

Time Source Content
7:47:07   rotation
7:47:10   [A weak humming noise can be heard for a few seconds]
7:47:11 FC Gear up
7:47:12 FO [Chime] - Gear up selected
7:47:19   [A faint 'rumbling' noise can be heard]
7:47:26 DEP Swedline 780 reduce to (old) speed
7:47:30 LF Seven eight zero reducing
7:47:31   [1st engine surge]
7:41:34   [Middle marker is heard for 16 seconds]
7:47:36 FO .. ?? .. ??
7:47:38   [2nd surge]
7:47:39   [Two 'clicks' from anti-ice switches]
7:47:41   [3rd surge]
7:47:42 FO Tror det är... kompressorstall (Believe it is ... compressorstall]
7:47:44   [4th surge]
7:47:46   [5th surge]
7:47:47   [6th surge]
7:47:49   [7th surge]
7:47:50   [8th surge]
7:47:52   [9th surge]
7:47:54 FO (Va är ..?? ... till det här.. ??)
7:47:55   [10th surge]
7:47:57   [11th surge]
7:47:59   [12th surge]
7:48:02   [13th surge]
7:48:03   [14th surge]
7:48:05   [Warbler + Autopilot (autopilot disengage warning. This warning remains on for the rest of the flight, except when interrupted by other warnings]
7:48:07   [16th surge]; surge no 16 starts here and is followed by several surges, partly disguised by the warnings
7:48:13   [3x chimes (cabin to cockpit call)]
7:48:15 CA2 .... Halla ......... [about 10 sec of heavy noise from engine stalls in background]
7:48:16 DEP Swedline 780 turn left heading heading 030, cleared for approach runway zero one
7:48:21 LF Left heading 030, cleared for approach zero one, Swedline 780
7:48:22   [chime (cabin to cockpit call)]
7:48:23   [Last engine surge can be heard]
7:48:27 DEP Swedline 780
7:48:49 FC Engine relight, engine relight!
7:48:32 FO Checked
7:48:37   [Fire bell (5 shot interval high pitch tones)+ fire left engine]
7:48:40 FO Ska jag dra?
7:48:41   [chime]
7:48:42   [Switch of CVR tape direction]
7:48:44 FO? (Svarar vänstermotorn?)
7:48:44 FO Arlanda.... Stockholm SK 74... 751
7:48:51 DEP Ja godmorgon SK751, climb to FL180, no speed restriction
7:48:56 FO We have problems with our engines, please... [clicks from switches, talk and autopilot disconnect warning in the background]... we need to go back to, ... to go back to Arlanda
7:49:02 FC (Har vi en) restart procedure?
7:49:04   ['Click' (from switch)]
7:49:05 DEP 751, roger, turn right heading 18... [power interrupts] ... turn righ...
7:49:06   [Two double chimes (bing-bong, bing-bong). CA2 caling CA1]
7:49:09 FC2 Titta [power interrupt] fram
7:49:09   [Electrical power interrupt no.1]
7:49:10 CA1 Jaa
7:49:10   [Electrical power interrupt no.2]
7:49:11   [Electrical power interrupt no.3]
7:49:12   [Electrical power interrupt no.4]
7:49:12   [Electrical power interrupt no.5]
7:49:12 CA Ja
7:49:12 CA2? Ja
7:49:13 FC2 Titta takt fram
7:49:13 CA2 Det är en... Jag tror att der är en pilot som sitter här bak, han säger att höger motor stallar jag vet inte vad det betyder
7:49:13 FC Yes
7:49:14   [Electrical power interrupt no.6]
7:49:17 CA1 Ja, höger motor staller ...... [several power interrupts and chimes are heard; microphone is 'open' for about 17sec]
7:49:18 FC (Prepare for emergency)
7:49:19 FC2 Ja titta rak, titta rakt fram, titta rakt fram!
7:49:22 FC Yes!
7:49:24   [One power interrupt followed by stabilizer motion horn]
7:49:27 FC2 Titta rakt fram!
7:49:27   [about 9 power interrupts during 7 seconds]
7:49:30   ['Click' (from switch)]
7:49:31 DEP SK751 are you able to turn right heading 090 radar vectoring for zero one.... [several power interrupts]
7:49:36   [Last power interrupt that can be heard]
7:49:36 CA1 Höger motor staller [heard in background]
7:49:37 FO Roger.. we are maintaining heading right now but we are trying to make a restart of the engines and make a slow turn to the left
7:49:41 FC (Engine) restart checklist
7:49:46 DEP Roger, you can maintain 2000ft also
7:49:47   [Noise from high energy ignition. On for the rest of the flight]
7:49:48 FC2 Titta rakt fram, titta rakt fram!
7:49:50 FC Yes
7:49:50 FO We are not able to maintain 2000ft, we are descending we are now at 1600 descending
7:49:55   [Stabilizer motion horn]
7:49:57 FC Prepare for an on ground emergency!
7:50:02 FC2 Ja titta rakt fram titta rakt fram
7:50:03 LF Swedline 780 established 01
7:50:05 FC Checked
7:50:06 DEP 780 Tower 118.5
7:50:10 LF 118.5, hej
7:50:10 CA1 Sätt dig i cockpit! [Asks FC2 to sit down]
7:50:12 FC Prepare for on ground emergency!
7:50:13 FC2 [Shouting] On ground emergency!
7:50:15 FC On ground emergency!
7:50:16 FC2 Titta rakt fr.., titta rakt fram!
7:50:21 DEP Swedline 208, climb to Flight Level 190
7:50:24 FC2 Titta rakt fram
7:50:24 FC Checked?
7:50:25 LF Flight level 190, Swedline two three, correction 208
7:50:25   [Horn and 'landing gear']
7:50:28 FC2 Titta rakt fram, ... ut
7:50:30   [Horn and landing gear (intermittently with autopilot warning until end of flight)]
7:50:31 CA1 On ground emergency
7:50:35 FC (Flaps eh eh)
7:50:36 FC2 a vi har flaps, vi har flap, titta rakt fram, titta rakt fram!
7:50:39 FC Yes
7:50:42 CA1 Sätt dej ner
7:50:43 FC2 Du fly..., nej du flyger
7:50:44   [Sound from switch?]
7:50:44 FC Yes
7:50:45 FC2 Välj en plats, höger, höger, höger, ... höger, höger, ... styr höger, styr höger
7:50:51 CA1 Keep your sear belts fastened
7:50:51 FC ..Checked..checked
7:50:53 CA1 Keep calm
7:50:54 FC2 Ja rakt fram där, rakt fram där, rakt fram (rakt mot skogen)
7:50:55   [Too low gear (from GPWS)]
7:50:57 FC2 Ja rakt mot skogen
7:50:57   [Too low gear]
7:50:57 FO Ska vi ta ut hjulen?
7:50:58 CA1 Bend down, hold your knees.. [chime]... ja
7:50:58 FC2 Ja gear down, gear down
7:50:59   [Whoop- whoop pull up (Continues for 11 seconds and is then replaced by 'Sinkrate']
7:50:59   [Chime from gear down]
7:51:01 FC2? (Nä gear down??)
7:51:03 FC2 Styr rakt fram
7:51:04 FC2 ..??..?? [Could be: 'Upp(ge plats), upp(ge plats)'
7:51:05 FO Och Stockholm SK751, vi havererar i marken nu
7:51:06   [Stabilizer motion horn]
7:51:10   [Sink rate + 1 second Stabilizer motion horn + Sink rate]
7:51:12   [3.40 seconds of sounds from crash]
7:51:15   [End of recording]

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