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Cases › DCA21FA085 › The analyst

BOEING 777-222United Airlines

What the docket says, assembled. No language model is involved, so nothing on this page can be invented — every line traces to a recorder, a report page or the Board's own record.

29
timed facts
8
precedents
78
passages to ask

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passages, not paraphrases
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Every answer is a passage of the docket with the page it came from, or the words “not in the docket”. Nothing is summarised or reasoned for you — read the source.

One timeline

29 timed factsthe recorder events from the FDR report, with the transcript's warnings, callouts, the words nearest each event and the final seconds — on one clock, as printed in each report
  1. 12:59:38.5CVR RDO-2p.9
    “coming out three whiskey with A-TIS. 12:59:52.2 united three twenty eight heavy denver ground. runway two”
    read in context ↗
  2. 13:02:38.6CVR ATCTcalloutp.12
    “calm runway two five cleared for takeoff.”
    read in context ↗
  3. 13:04:40FDRTakeoffp.6
    Aircraft taxied and subsequently took off from Denver International Airport (DEN), Denver, Colorado, with no readily apparent issues
    see the traces at this moment ↗
  4. 13:08:23FDRClimbp.6
    At a pressure altitude of 12,110 ft, engine power was slightly increased, consistent with an application of power to increase climb rate
    see the traces at this moment ↗
  5. 13:08:33FDRClimb - Engine Eventp.6
    Upon reaching a pressure altitude of approximately 12,570 ft, multiple parameters associated with the right-hand engine (engine 2) dropped significantly, including N1, N2, EPR, and fuel flow, while the exhaust gas temperature (EGT) noticeably raised in comparison to engine 1
    see the traces at this moment ↗
  6. shortly after 13:08:33FDREngine Eventp.6
    Numerous vibrations were recorded in the right-hand engine, and both engine 2 fire warning parameters activated
    see the traces at this moment ↗
  7. 13:08:45.9CVR RDO-2warningp.18
    “engine failure. we need to turn.”
    read in context ↗
  8. 13:08:58.3CVR RDO-2warningp.18
    “eight heavy mayday mayday aircraft uh. 13:09:02.3 united three twenty eight heavy just got here. uh- say again TRACON please.”
    read in context ↗
  9. 13:09:45.1CVR RDO-1p.20
    “eight heavy.”
    read in context ↗
  10. 13:09:50FDRDescent Initiationp.6
    Aircraft reached a maximum pressure altitude of 13,456 ft, then began a descent
    see the traces at this moment ↗
  11. 13:11:47FDRPost-Eventp.6
    Fire bottle 2 was discharged
    see the traces at this moment ↗
  12. 13:12:36FDRPost-Eventp.6
    Fire bottle 1 was discharged
    see the traces at this moment ↗
  13. 13:13:30FDRDescent levelingp.6
    Aircraft reached 9,200 ft and remained there
    see the traces at this moment ↗
  14. 13:13:38.0CVR CAM-2p.24
    “we're returning to denver? DCA21FA085 Time and Time and Source Source”
    read in context ↗
  15. 13:18:42.1CVR RDO-1calloutp.31
    “heavy. united three twenty eight heavy you can have uh- any runway 13:18:59.8 you like so just let me know um- keeping you wide there if you TRACON want to go into the west runways or i can take you up to the north and take you to the south runways it's really your call.”
    read in context ↗
  16. 13:21:16FDRPost-Eventp.6
    Engine 2 fire warnings remained activated until this time
    see the traces at this moment ↗
  17. 13:21:25.9CVR RDO-2p.36
    “heavy.”
    read in context ↗
  18. 13:23:30FDRApproachp.6
    Aircraft began its descent towards DEN
    see the traces at this moment ↗
  19. 13:24:05.6CVR CAM-1final secondsp.39
    “uh- be on the ground just a couple minutes and uh-”
    read in context ↗
  20. 13:24:19.4CVR CAM-2final secondsp.39
    “just plan uh to be remain seated. yeah just uh- at least right now.”
    read in context ↗
  21. 13:24:48.1CVR RDO-1final secondsp.40
    “heavy. seven thousand. inbound runway two six. DCA21FA085 Time and Time and Source Source”
    read in context ↗
  22. 13:25:04.9CVR CAM-1final secondsp.41
    “something to shake that bad.”
    read in context ↗
  23. 13:26:07.8CVR RDO-2final secondsp.42
    “and we just have the uh- have them follow us.”
    read in context ↗
  24. 13:26:20.8CVR CAM-1final secondsp.42
    “vibration drops way off. 13:26:38.0 god #. okay let's go flaps twenty. set the approach”
    read in context ↗
  25. 13:26:20.8CVR CAM-1final secondsp.42
    “speed for me. DCA21FA085 Time and Time and Source Source”
    read in context ↗
  26. 13:27:17.9CVR CAM-1final secondsp.44
    “land. * stable.”
    read in context ↗
  27. 13:28:10FDRLandingp.6
    Aircraft touched down
    see the traces at this moment ↗
  28. 13:29:12FDRLandingp.6
    Aircraft stopped on the runway
    see the traces at this moment ↗
  29. 13:34:11FDRPost-Landingp.6
    Recording ended; aircraft remained stationary for the remainder of the recording
FLIGHT DATA RECORDER - SPECIALISTA��S FACTUAL REPORT · 13 events extracted by claude-sonnet-5COCKPIT VOICE RECORDER - GROUP CHAIR'S FACTUAL REPORT · 16 of 37 lines shown
How the Board coded the sequence
  1. Initial climb: Powerplant sys/comp malf/fail

Precedents

8 closest casesranked by what happened, in the Board's words, and by the findings and occurrences it coded
  • ENG09IA0022009-01-02no fatalitiesmatch 79
    BOEING 777 · Delta Air Lines
    Atlanta, GA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    • ●Organizational issues › Development › Design
    Powerplant sys/comp malf/fail
  • DCA18MA1422018-04-171 fatalmatch 73
    BOEING 737 7H4 · SOUTHWEST AIRLINES CO
    Philadelphia, PA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG11IA0352011-06-21no fatalitiesmatch 69
    BOEING 757-232 · DELTA AIR LINES INC
    Atlanta, GA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    • ●Organizational issues › Development › Design
    Powerplant sys/comp malf/fail
  • DCA16FA2172016-08-27substantialmatch 66
    BOEING 737-700 · Southwest Airlines
    Pensacola, FL
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG17IA0282017-06-10no fatalitiesmatch 65
    BOMBARDIER INC CL 600 2C10 · SKYWEST AIRLINES INC
    Chicago, IL
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG17IA0082017-01-23no fatalitiesmatch 61
    BOMBARDIER INC CL 600 2B19 · Endeavor Air
    Baltimore, MD
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG11IA0432011-08-06no fatalitiesmatch 61
    MCDONNELL DOUGLAS DC-9-51 · Delta Air Lines
    Atlanta, GA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
  • ANC08IA0922008-07-29no fatalitiesmatch 59
    Saab-Scania AB (Saab) SAAB 340B · PENINSULA AIRWAYS INC
    Anchorage, AK
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail

What the record says

a pattern, not a findingacross the 8 closest cases · 8 carry coded findings · 8 have a probable cause
Findings the Board cited in those cases
Occurrences it coded
  • 7 of 8Powerplant sys/comp malf/fail
Set against the Board’s own findings for this case
Cited here, and common in the precedents
  • Aircraft power plant › Engine (turbine/turboprop)
  • Development › Design
Cited here, not seen in the precedents
  • Aircraft handling/service › Maintenance/inspections
Common in the precedents, not cited here
  • Aircraft structures › Nacelles/pylons structure

A teaching device, not a verdict: what the record would have looked at, next to what the Board found.

In the Board’s words — the closest cases
  • ENG09IA0022009-01-02 · BOEING 777 · Delta Air Lines
    The fan blade fractured due to a fatigue crack that was the result of the combination of the breakdown of the fan blade lubrication system and residual fatigue life usage following the last overhaul of the fan blade. Contributing to the fracture was the inadequate lubrication schedule established by the engine manufacturer that was not reflective of the operator’s use of the engine.
  • DCA18MA1422018-04-17 · BOEING 737 7H4 · SOUTHWEST AIRLINES CO
    A low-cycle fatigue crack in the dovetail of fan blade No. 13, which resulted in the fan blade separating in flight and impacting the engine fan case at a location that was critical to the structural integrity and performance of the fan cowl structure. This impact led to the in-flight separation of fan cowl components, including the inboard fan cowl aft latch keeper, which struck the fuselage near a cabin window and caused the window to depart from the airplane, the cabin to rapidly depressurize, and the passenger…
  • ENG11IA0352011-06-21 · BOEING 757-232 · DELTA AIR LINES INC
    Fuel leaking from the fuel flow transmitter that ignited on contact with the engine’s hot cases which resulted in an engine undercowl fire. The fuel leak resulted from the fuel flow transmitter end housing backing off from the main housing, creating a gap that allowed high pressure fuel to escape. Under certain assembly variances and operational load and temperature variations, the end housing joint may not be able to maintain the preload without eventually yielding, which results in the loosening of the joint and…
  • DCA16FA2172016-08-27 · BOEING 737-700 · Southwest Airlines
    A low-cycle fatigue crack in the dovetail of fan blade No. 23, which resulted in the fan blade separating in flight and impacting the fan case. This impact caused the fan blade to fracture into fragments that traveled farther than expected into the inlet, which compromised the structural integrity of the inlet and led to the in-flight separation of inlet components. A portion of the inlet struck the fuselage and created a hole, causing the cabin to depressurize.
  • ENG17IA0282017-06-10 · BOMBARDIER INC CL 600 2C10 · SKYWEST AIRLINES INC
    A Bombardier CRJ700 No. 1 engine failure caused by buckling of the combustion outer liner due to fatigue cracks. The liner buckling resulted in airflow disruption and reduced engine performance. The engine fuel control unit attempted to compensate for the decrease in engine performance by increasing the fuel flow rate. The combustion liner damage and increased fuel flow led to incomplete combustion of the fuel injected into the combustion chamber. Unconsumed fuel then ignited downstream of the combustion chamber (d…
What it recommended after them
  • A-19-017TO THE FEDERAL AVIATION ADMINISTRATION: Require Boeing to determine the critical fan blade impact location(s) on the CFM56-7B engine fan case and redesign the fan cowl structure on all Boeing 737 next-generation-series airplanes to ensure t… · DCA18MA142Closed - Acceptable Action
  • A-19-018TO THE FEDERAL AVIATION ADMINISTRATION: Once the actions requested in Safety Recommendation A-19-17 are completed, require Boeing to install the redesigned fan cowl structure on new-production 737 next-generation-series airplanes. · DCA18MA142Open - Acceptable Response
  • A-19-019TO THE FEDERAL AVIATION ADMINISTRATION: Once the actions requested in Safety Recommendation A-19-17 are completed, require operators of Boeing 737 next-generation-series airplanes to retrofit their airplanes with the redesigned fan cowl str… · DCA18MA142Open - Acceptable Response
  • A-19-020TO THE FEDERAL AVIATION ADMINISTRATION: Expand the Title 14 Code of Federal Regulations Part 25 and 33 certification requirements to mandate that airplane and engine manufacturers work collaboratively to (1) analyze all critical fan blade i… · DCA18MA142Open - Acceptable Response
  • A-19-021TO THE FEDERAL AVIATION ADMINISTRATION: Develop and issue guidance on ways that air carriers can mitigate hazards to passengers affected by an in-flight loss of seating capacity. · DCA18MA142Closed - Unacceptable Action
  • A-19-022TO SOUTHWEST AIRLINES: Include the lessons learned from the accident involving Southwest Airlines flight 1380 in initial and recurrent flight attendant training, emphasizing the importance of being secured in a jumpseat during emergency lan… · DCA18MA142Closed - Acceptable Action
  • A-19-023TO THE EUROPEAN AVIATION SAFETY AGENCY: Expand your certification requirements for transport-category airplanes and aircraft engines to mandate that airplane and engine manufacturers work collaboratively to (1) analyze all critical fan blad… · DCA18MA142Open - Acceptable Response

This is the pattern in the NTSB’s own record across similar accidents — which findings it cited, what it coded, what it recommended. It is drawn from the record, not written about this case, and it never assigns blame: investigations exist to prevent the next accident (ICAO Annex 13).