FlarePath
Cases › DCA16FA217 › The analyst

BOEING 737-700Southwest 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.

5
timed facts
8
precedents
18
passages to ask

Ask the docket

passages, not paraphrases
Try

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

5 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. 9:04:34 CDT (96,524 SRN)FDRPre-takeoffp.3
    FDR data begins recording before takeoff
  2. 9:21:46 CDT (97,555 SRN)FDRClimbp.3
    Discontinuity of the FDR data most likely due to the engine failure while climbing through a pressure altitude of about 31,259 ft; engine 1 N1 at 99% RPM
  3. 9:21:49 CDT (97,559 SRN)FDRClimbp.3
    Engine 1 N1 decreased to 39% RPM and pressure altitude increased slightly to 31,341 ft
  4. 9:22:18 CDT (97,588 SRN)FDRClimb/Depressurizationp.3
    Cabin altitude warning (Cabin Alt Warn) transitioned from No Warn to Warn and remained at Warn for the rest of the FDR data; engine 1 N1 decreased to 33% RPM and pressure altitude decreased to 31,068 ft
  5. 9:29:37 CDT (98,027 SRN)FDRDescentp.3
    FDR data ended; last recorded pressure altitude was 17,413 ft and last recorded engine 1 N1 was 17% RPM
Flight Data Recorder - Specialist’s Factual Report · 5 events extracted by claude-sonnet-5
How the Board coded the sequence
  1. Enroute: Powerplant sys/comp malf/fail→
  2. Enroute-cruise: Pressure/environ sys malf/fail

Precedents

8 closest casesranked by what happened, in the Board's words, and by the findings and occurrences it coded
  • DCA18MA1422018-04-171 fatalmatch 80
    BOEING 737 7H4 · SOUTHWEST AIRLINES CO
    Philadelphia, PA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    • ●Aircraft › Aircraft structures › Nacelles/pylons structure
    Powerplant sys/comp malf/fail
  • DCA21FA0852021-02-20no fatalitiesmatch 66
    BOEING 777-222 · United Airlines
    Broomfield, CO
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG09IA0022009-01-02no fatalitiesmatch 63
    BOEING 777 · Delta Air Lines
    Atlanta, GA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG17IA0082017-01-23no fatalitiesmatch 62
    BOMBARDIER INC CL 600 2B19 · Endeavor Air
    Baltimore, MD
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG08IA0382008-08-06no fatalitiesmatch 62
    BOEING 757 · DELTA AIR LINES INC
    Las Vegas, NV
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG11IA0432011-08-06no fatalitiesmatch 59
    MCDONNELL DOUGLAS DC-9-51 · Delta Air Lines
    Atlanta, GA
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
  • ENG12IA0122012-02-13no fatalitiesmatch 57
    MCDONNELL DOUGLAS MD-10-30F · FEDERAL EXPRESS CORPORATION
    Portland, OR
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)
    Powerplant sys/comp malf/fail
  • ENG17IA0262017-06-07no fatalitiesmatch 57
    BOEING 747 451 · Delta Air Lines
    Tokyo, JP
    • ●Aircraft › Aircraft power plant › Engine (turbine/turboprop)

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
  • 6 of 8Powerplant sys/comp malf/fail
  • 2 of 8Engine shutdown
  • 2 of 8Uncontained engine failure
Set against the Board’s own findings for this case
Cited here, and common in the precedents
  • Aircraft power plant › Engine (turbine/turboprop)
Cited here, not seen in the precedents
  • Aircraft structures › Fuselage
Common in the precedents, not cited here
  • Development › Design

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
  • 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…
  • DCA21FA0852021-02-20 · BOEING 777-222 · United Airlines
    The fatigue failure of the right engine fan blade. Contributing to the fan blade failure was the inadequate inspection of the blades, which failed to identify low-level indications of cracking, and the insufficient frequency of the manufacturer’s inspection intervals, which permitted the low-level crack indications to propagate undetected and ultimately resulted in the fatigue failure. Contributing to the severity of the engine damage following the fan blade failure was the design and testing of the engine inlet, w…
  • 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.
  • ENG17IA0082017-01-23 · BOMBARDIER INC CL 600 2B19 · Endeavor Air
    A Bombardier CRJ200 No. 2 engine failure due to the separation of a fan blade airfoil at a low cycle fatigue crack that originated at the forward fan blade pin hole attachment. The separated fan blade had previously undergone a hot form repair and both metallurgical analysis and repair records indicated that the lance/shot peen step required to restore sufficient residual stress levels to the blade material was not completed.
  • ENG08IA0382008-08-06 · BOEING 757 · DELTA AIR LINES INC
    The engine experienced an uncontained release of high pressure turbine material due to fatigue cracks that occurred on four consecutive blade retainig lugs on the 2nd stage turbine hub. The cracked lugs resulted in the release of four 2nd stage turbine blades that penetrated the engine's cases and nacelle. The lugs cracked due to loss of material and resultant increase in stress load on the blade slot serrations due to excessve grit blasting when the hub was being overhauled by Delta Air Lines. Contributing to the…
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
  • A-08-085TO THE FEDERAL AVIATION ADMINISTRATION: Require that Pratt & Whitney PW2037 engines be removed from service for inspection of the 2nd stage turbine hubs when they have accumulated significantly fewer hours and/or cycles than the incident en… · ENG08IA038Closed - Unacceptable Action

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).