# NTSB DCA17WA159: Boeing 747 422, N121UA, Frankfurt, Germany, July 18, 2017

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Foreign investigation
- Date: July 18, 2017
- Place: Frankfurt, Germany
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute: Pressure/environ sys malf/fail](https://openairdocs.org/ntsb-events/331)
- Highest injury: No injuries
- Status: Led by another country's authority
- NTSB office: Major Investigations Division
- Lead agency: Other
- NTSB case key (mKey): 95663
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DCA17WA159
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95663/pdf
- Page: https://openairdocs.org/ntsb/DCA17WA159

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute: Pressure/environ sys malf/fail](https://openairdocs.org/ntsb-events/331) (defining event); cases with it: [Boeing 747-422, 1 case](https://openairdocs.org/ntsb-events/331/sequence.md?model=1384935), [All aircraft, 116 cases](https://openairdocs.org/ntsb-events/331/sequence.md)

## Factual narrative

The BFU of Germany has notified the NTSB of an incident involving a Boeing 747 airplane that occurred on July 18, 2017. The NTSB has appointed a U.S. Accredited Representative to assist the BFU's investigation under the provisions of ICAO Annex 13 as the State of Manufacturer and Design of the airplane.All investigative information will be released by the BFU of Germany.

## Aircraft

- Registration: [N121UA](https://openairdocs.org/deregistered/N121UA-2018-01-19), registration cancelled 2018-01-19, S/N 29167, built 1999 (OpenAirDocs)
- Reported make and model: BOEING 747 422 (422)
- Registry model: [Boeing 747-422](https://openairdocs.org/model/boeing-747-422) (registry code 1384935) (OpenAirDocs)
- Category: Airplane
- Serial number: 29167
- Engines: ; ; ; 
- Damage: No damage
- Operator: United Airlines
- Registered owner: United Airlines Inc

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.

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