FlarePathAir-accident investigation intelligence

Investigation brief · generated 2026-10-09 · source: NTSB public docket and accident database

Airbus A320 — Newark, NJ, USA, 2008-01-25

NTSB number

DCA08IA033

Operator

United Airlines Inc

Registration

N462UA

Highest injury

No injury

Regulation

Part 121

Damage

—

Cohort

Part 121 airline

Recorder data

Tier 1 — decoded recorder tables

Every sentence below is taken directly from NTSB records — the accident database, the docket's recorder reports and the Board's findings — with its source noted. Nothing is paraphrased or inferred.

NTSB summary

This incident occurred when United Airlines flight 731 experienced a fault in the airplane's AC 1 electrical bus, one of the two primary electrical distribution systems for the airplane, which in turn caused a number of other electrical busses on the aircraft to lose power. The loss of this electrical power led to the loss of a number of aircraft displays and systems. During the flights return to the airport, multiple messages on the electronic centralized aircraft monitoring (ECAM) system, which provides information to the crew regarding failures that have occurred on the aircraft along with recommended corrective actions, were being displayed then removed by the ECAM system, making it difficult for the flight crew to interpret and address the error messages. There were no faults found in the airplane wiring and the testing and teardown found don faults in the #1 integrated drive generator (IDG), bus tie contactor (BTC), and generator control unit (GCU).

Verbatim, NTSB aviation accident database (narratives.narr_accf).

Probable cause

a fault in the airplane's AC 1 electrical bus that caused a number of other electrical busses on the aircraft to lose power.

Verbatim, NTSB determination.

Flight data recorder

— 65,532 samples, 24 parameters, SRN 182,400 to SRN 184,059.

Parameter	Max	at	Min	at	Final	at
Pitch attitude deg	17.6	SRN 182,875	-1.1	SRN 183,422	-0.4	SRN 184,059
Vertical acceleration g	1.3	SRN 182,870	0.6	SRN 182,474	0.9	SRN 184,059
Magnetic heading deg	359.3	SRN 183,162	1.8	SRN 183,163	284.4	SRN 184,058

Computed from the docket's tabular attachment; times as recorded (local or SRN as published).

Sequence of events (FDR factual report)

Time	Event	Page
takeoff	Aircraft took off at an indicated airspeed of approximately 170 knots and began to climb	3
about 10 seconds after liftoff	DC Bus ESS, AC Bus ESS and AC Bus 1 parameters turned from on to off; autopilot parameters began recording non-computed data	4
about 2 minutes later	Altitude and airspeed parameters began recording non-computed data	4
13 minutes 15 seconds after takeoff	Aircraft landed at Newark	4
about 7 minutes after landing	DC Bus ESS and AC Bus ESS turned on; altitude and autopilot parameters resumed recording valid data	4

Extracted by claude-fable-5-1 (in-session); 3 of 5 stated events verified against the raw recorder data.

Recorder documents in the docket

Group	Title	Pages	Type
fdr	Flight Data Recorder 10 - Factual Report of Group Chairman	6	pdf
fdr	Flight Data Recorder 10 - Attachment 1 FDR Tabular		csv

Docket: data.ntsb.gov/Docket/?NTSBNumber=DCA08IA033. This brief is an analytical aid assembled from public records; it is not an investigative finding.