CVR transcript United Air Lines Flight 553 - 08 DEC 1972
Last updated: 16 October 2004
Cockpit voice recorder transcription of the December 8, 1972 crash of a United Air Lines Boeing 737 (Flight 553) at Chicago, IL.
Source: NTSB-AAR-73-16

The reader of these transcripts is cautioned that the transcription of a CVR tape is not a precise science but is the best possible product from a group investigative effort. The transcript, or parts thereof, if taken out of context can be misleading. Therefore, the CVR transcripts should only be viewed as an investigative tool to be used in conjunction with other evidence. Conclusions or interpretations should not be made using the transcript as the sole source of information.
Furthermore, this transcript is made available for educational purposes, so the reader is encouraged to read the accident description associated with the transcripts for better understanding of the circumstances.

Legenda CAM - Cockpit area microphone
RDO - Radio transmission from accident aircraft
-1 - Voice identified as Captain
-2 - Voice identified as First Officer
-3 - Voice identified as Second officer
-? - Unidentifiable voice
CHI APP = Chicago Approach
MTWR = Chicago-Midway Tower
* - Unintelligible word
# - Expletive deleted
() - Questionable text
9VS = Aero Commander 690, N309VS pilot
time source content
20.25:25.0 CHI APP Five five three, call the tower on one eighteen seven
20.25:28.0 RDO-2 Eighteen seven, five five three
20.25:35.5 RDO-2 Midway tower, United five five three, an' we'r out of three for two
20.25:39.0 MTWR United five five three, report passing the outer marker, number two on the approach
20.25:41.0 CAM-3 Chicago, this is five five three (2nd officer calling ARINC)
20.25:44.0 RDO-2 Okay, report the outer marker
20.25:46.5 CAM-1 Let's have the gear down please
20.25:48.0 RDO-1 [Start of first sound of first series off Kedzie outer marker beacon tones]
20.25:50.97 CAM-3 Chicago, five five three (2nd officer calling ARINC)
20.25:51.62 CAM [Sound of a click - sound similar to sound of landing gear handle going into down detent]
  CAM [Sound of chime - simultaneous with click above]
20.25:52.20 MTWR Nine Victor Sugar, what's your airspeed?
20.25:54.5   [End sound of first series of Kedzie outer marker beacon tones]
20.25:54.74 9VS Ah, we're down to ah, hundred twenty knots
20.25:55.06 CAM [Increase in ambient noise level - similar to increase made by nose landing gear extended]
20.25:56.82 MTWR Ah hundred and twenty, okay
20.26:00.64 CAM [Sound of first of four clicks in rapid increase - sounds similar to flap lever moved from 15 degrees to 25 degrees position]
20.26:01.50 CAM-? Gear 'own
  CAM [Sound of several clicks - similar to sound of stabilizer trim actuation]
20.26:10.02 RDO-1 [Sound of beginning of second series of Kedzie outer marker beacon tones]
20.26:20.02 RDO-1 [End of sound of second series of Kedzie outer marker beacon tones]
20.26:24.66 CAM-1 Final descent check
20.26:25.66 CAM-3 Flight and nav
20.26:27.11 CAM-2 Cross-checked
  CAM-? * * *
  CAM [Sound of clicks - similar to sound of stabilizer trim actuation]
20.26:30.62 RDO-2 United five five three, an, ah Kedzie inbound
20.26:35.97 CAM-? Flight
20.26:36.38 MTWR United five five three, continue inbound, you're number two on the approach --'ll keep you advised.
20.26:40.10 CAM [Sound of several clicks - similar to sound of electrical stabilizer trim actuation]
20.26:40.47 RDO-2 Okay
20.26:40.96 CAM-2 Cross-checked
  CAM-3 With a glideslope flag
  CAM-2 No glideslope
20.26:41.10 9VS Eh, nine VS has the runway
20.26:43.06 MTWR Nine VS, runway three one left cleared to land
20.26:44.67 CAM-3 Aaan the --- landing gear
20.26:46.18 9VS Okay
20.26:48.40 MTWR Nine VS, do ya have the right runway in sight by any chance?
20.26:50.41 CAM-2 Down, three greens
20.26:51.37 CAM-3 Speed brake?
20.26:51.37 9VS Affirmative
20.26:52.45 CAM-2 Ah --- armed
20.26:52.6 MTWR 'ud you swing over to that and land? There's a jet about two m-- and disregard that, ah, okay, I see ya now, you'r cleared to land on thirty-one left
20.26:54.69 CAM [Sound of click - similar to sound made by moving speed brake lever to armed position]
20.26:56.04 CAM-3 Wing flaps
20.26:58.75 CAM [Sound of click - similar to sound made by flap lever moving into detent]
20.26:59.42 CAM-2 Thirty, green light, pressure fluid.
20.27:01.48 CAM-3 An the auto-pilot?
  CAM [Sound of click - similar to electrical stabilizer trim actuation]
20.27:02.96 CAM-2 Disarmed
20.27:04.11 CAM-2 Ah thousand feet
20.27:04.50 MTWR United five fifty-three, execute a missed approach, make a left turn to a heading of --- one eight zero, climb to two thousand [between words 'of' and 'one' there is a pause and a voice in the background says 'one eighty']
20.27:05.74 CAM [Sound of stickshaker begins and continues to end of recording]
20.27:07.56 CAM-? [Two to three hurried word at very low amplitude and masked by noise of stickshaker]
  CAM [Sound of click - similar to sound made by flap lever moving into detent]
20.27:12.14 RDO-2 Okay, left turn to one eight zero, --- left turn okay?
20.27:13.88 CAM-3 Want more flaps?
20.27:15.33 CAM-? Flaps fifteen.
20.27:15.45 MTWR Yeah, make left turn to one eighty.
20.27:16.14 CAM-? I'm sorry.
20.27:16.47 CAM [Sound of click - similar to sound made by flap lever moving into detent]
20.27:19.4 CAM [Sound of click - similar to sound made by landing gear lever moved out of detent]
20.27:20.14 CAM [Sound of double click - similar to sound made by landing gear lever moved into up detent]
20.27:10.64 CAM [Sound of landing gear warning horn begins and continues to end of recording]
20.27:23.55 CAM [Sound of initial impact and garbled voice]
20.27:24.46 RDO-1 [Sounds of impact and unintelligible voice]
20.27:25.02 RDO-1 end of recording.