# NTSB DCA24LA110: Boeing 757-224, N13138, San Francisco, CA, February 26, 2024 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: February 25, 2024, 21:02 local (Feb 26, 2024, 05:02 UTC) - Place: San Francisco, CA - Coordinates: 37.6193, -122.3816 - Nearby events: https://openairdocs.org/map.md?lat=37.6193&lon=-122.3816&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Abnormal runway contact](https://openairdocs.org/ntsb-events/090) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Major Investigations Division - Parties: United Airlines, FAA - NTSB case key (mKey): 193849 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA24LA110 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193849/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193849 - Page: https://openairdocs.org/ntsb/DCA24LA110 ## Probable cause The crew’s over-rotation of the aircraft pitch during takeoff which resulted in a tailstrike. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Boeing 757-224, 1 case](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=1384958), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Abnormal runway contact](https://openairdocs.org/ntsb-events/090) (defining event); cases with it: [Boeing 757-224, 1 case](https://openairdocs.org/ntsb-events/090/sequence.md?model=1384958), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md) ## Analysis United Airlines (UA) flight 3872 experienced a tailstrike while taking off from San Francisco International Airport (SFO), San Francisco, California. The flight was a local maintenance test flight. The purpose of the test flight was to validate maintenance conducted after a write-up for abnormal flight deck noises that occurred on a previous flight. According to the flight crew, they conducted a flaps 5, reduced power takeoff from runway 28R. The captain recalled the aircraft accelerated faster than normal and had the propensity to lift off prior to the rotation speed of 127 knots. At rotation speed, the captain began a normal aft pull on the control yoke and the pitch attitude increased faster than expected. The captain just called “positive rate” when the crew heard and felt a “boom.” As this flight was a test flight, it was not loaded with passengers and cargo to a takeoff weight typical of flights the pilot flying normally flew. The pilot flying rotated at a rate “normal” to his experience, however because the accident aircraft was loaded lighter than normal, the normal rotation inputs resulted in an over-rotation. The crew assessed the instruments and controllability and decided to continue their climb to flight level (FL) 190 [19,000 feet] where they conducted the tailstrike checklist. They returned to SFO and conducted a flaps 30 landing with no further incident. Prior to leaving the flight deck after the flight, the first officer received the pitch report for takeoff which showed that tail contact occurred about 12.2 degrees during departure and the actual pitch for this departure reached 15.3 degrees. Inspection of the aircraft showed that the tail strike damaged the chord, web, and stiffeners of the auxiliary power unit firewall bulkhead. Because the damage would adversely affect the structural strength of the bulkhead and require major repair or replacement, the damage was considered substantial. The investigation determined that the maintenance conducted prior to this test flight was not related to the accident. ## Aircraft - Registration: [N13138](https://openairdocs.org/aircraft/N13138), registered now, S/N 30351, built 1999 (OpenAirDocs) - Reported make and model: BOEING 757-224 - Registry model: [Boeing 757-224](https://openairdocs.org/model/boeing-757-224) (registry code 1384958) (OpenAirDocs) - Registry engine: [Rolls-Royce RB-211 series](https://openairdocs.org/engine/rolls-royce-rb-211-series) (registry code 54555, turbo-fan) (OpenAirDocs) - Category: Airplane - Serial number: 0138 - Year built: 1999 - Airframe hours: 85724 - Engines: ROLLS-ROYC RB-211-535E4B-37 42700 lbs thrust turbo fan; ROLLS-ROYC RB-211-535E4B-37 42700 lbs thrust turbo fan - Damage: Substantial damage - Flight: Flight test, Part 91 - Operator: United Airlines Inc - Registered owner: United Airlines Inc - Airworthiness certificate: Standard, Commuter; Standard, Transport; Standard, Normal - Last inspection: Continuous airworthiness, June 9, 2023 - Destination: Same as departure - Flight plan: IFR - Airport: SFO, San Francisco Intl, runway 10L/28R, 11,870 × 200 ft, concrete - Equipment: Electronic multifunction display, Electronic flight bag or handheld device, Data recorder, Auto-pilot, Angle of attack indicator, Electronic primary flight display, ADS-B, Stall warning system, Satellite tracking device, Onboard weather ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review October 10, 2023; seat: left; restraint: 5-point; flight hours: 15,575 total, 1,250 in this make and model, 3,100 as pilot in command, 230 in the last 90 days, 58 in the last 30 days - Co-pilot; age 31; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 1; last flight review February 17, 2024; seat: right; restraint: 5-point; flight hours: 2,471 total, 260 in this make and model, 434 as pilot in command, 135 in the last 90 days, 45 in the last 30 days ## Weather - Conditions: Visual (VMC), Night - Visibility: 10 statute miles - Lowest ceiling: 800 ft broken ## Other investigations on N13138 (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB DCA23LA477](https://openairdocs.org/ntsb/DCA23LA477), Feb 10, 2023: Boeing 757 (N13138), Lake Butler, FL, no damage. Probable cause: An inadvertent encounter with convectively induced turbulence. ## Docket (4 files) The files NTSB released with the investigation on July 17, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193849. 8.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 4.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17027438&FileExtension=pdf&FileName=NTSB%206120%20DCA24LA110_1_Redacted-Rel.pdf - Captain's statement (item 2, PDF, 2 pages, 86 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17027334&FileExtension=pdf&FileName=UA3872%20NTSB%20CA%20Statement%20-%20FINAL-Rel.pdf - First officer's statement (item 3, PDF, 2 pages, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17027231&FileExtension=pdf&FileName=UA3872%20NTSB%20FO%20Statement%20FINAL-Rel.pdf - Operator's aircraft damage photographs (item 4, PDF, 6 pages, 6 photos, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17027448&FileExtension=pdf&FileName=DamageReportFS-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.