Investigation brief · generated 2026-10-09 · source: NTSB public docket and accident database
BOMBARDIER INC DHC 8 402 — Pittsburgh, PA, USA, 2011-03-17
NTSB number
ENG11IA021
Operator
Colgan Air, Inc.
Registration
N339NG
Highest injury
No injury
Regulation
Part 121
Damage
Minor
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
A left engine aft thrust rotor bearing incipient spalling condition progressed to failure during cruise flight. The loss of rotor thrust support caused the rotor to displace aft and contact adjacent stationary structures, including structures in the No. 2 bearing area. The resulting machining-type contact damage generated metal debris that contaminated the engine oil. Metal particles in the oil scavenged from the No. 2/2.5 bearing oil cavity damaged the engine oil pump and arrested its rotation, which caused torsional separation of the oil pump driveshaft, cutting off oil supply to the engine. The left engine oil pressure master warning activated. The flight crew did not shut down the engine. The engine operated 84 seconds without oil flow, until combustor and turbine component fire damage disrupted combustor flame stability and the engine flamed out. The continued operation without oil flow elevated engine operating temperatures, and the No. 5 engine bearing cavity temperature increased beyond the material properties of the No. 5 bearing seal runner. The seal runner expanded radially and caused a hard rub against the (titanium-alloy) No. 5 bearing flexible support. The local temperature at the contact point rapidly reach its ignition temperature. The resulting titanium fire consumed the No. 5 bearing flexible support and progressed to adjacent thin-walled titanium components, including the diffuser diaphragm. Molten titanium droplets falling onto diffuser exit ducts located directly beneath the No. 5 bearing area melted through three of the exit ducts and penetrated the gas generator case. The titanium fire self-extinguished when the conditions required for sustained titanium combustion were altered by the flameout and the case burn-through. The lack of circumferential titanium droplet distribution, the undamaged condition of the diffuser ring bore internal surfaces, and the gravity-driven nature of the case penetration indicate that the titanium fire originated external to the diffuser/engine gas path. The cockpit engine fire warning remained active when no fire was present because one of the nacelle fire/overheat detector elements was unable to reset due to a permanently deformed switch diaphragm.
the flight crew's delay in shutting down the left engine following an engine oil pressure master warning, which led to a hard rub inside the engine that served as an ignition point for a titanium fire. Contributing to the event was a PW150 No. 5 seal design vulnerability to titanium ignition that can occur with continued engine operation following an engine oil pressure loss event.
Verbatim, NTSB determination.
Flight data recorder
· N339NG — 135,094 samples, 41 parameters, 12:00:00.0 to 12:49:59.9.
Parameter
Max
at
Min
at
Final
at
Pitch attitude deg
5.9
12:05:42.2
-3.4
12:41:43.7
-1.1
12:49:59.9
Roll attitude deg
25.4
12:10:36.7
-34.3
12:43:46.2
0.3
12:49:59.7
Vertical acceleration g
1.3
12:49:33.9
0.7
12:46:49.2
1.0
12:49:59.9
Computed from the docket's tabular attachment; times as recorded (local or SRN as published).
Sequence of events (FDR factual report)
Time
Event
Page
12:02:30 EDT
Weight on wheels main gear transitioned from 'Grnd' to 'Air'
3
12:27:32 EDT
Master warning transitioned from 'No Warning' to 'Warning'; engine 1 oil pressure transitioned from 'No Warn' to 'Warn' and remained 'Warn' for rest of flight
3
12:27:41 EDT
Master warning transitioned back to 'No Warning'
3
12:28:58 EDT
Engine 1 torque decreased to 58%, engine 2 torque remained 71%, engine 1 fuel flow decreased to 1,328 pph, engine 2 fuel flow remained 1,288 pph
3
12:29:00 EDT
Engine 1 torque decreased to 41%, engine 1 fuel flow decreased to 856 pph
3
12:29:08 EDT
Engine 1 torque decreased to 0%, engine 2 torque decreased slightly to 70%, engine 1 fuel flow increased to 1,312 pph, engine 2 fuel flow decreased slightly to 1,272 pph
3
12:29:10 EDT
Master warning transitioned back to 'Warning'; CWP Check Fire Det transitioned from 'No Warning' to 'Warning' and remained 'Warning' for rest of flight
3
12:29:18 EDT
Master caution transitioned from 'Off' to 'On'
3
12:29:27 EDT
Engine 1 fuel flow decreased to 0 pph
3
12:29:52 EDT
Master warning transitioned back to 'No Warning' and remained 'No Warning' for rest of flight
3
12:30:15 EDT
Master caution transitioned back to 'Off' and remained 'Off' for rest of flight
4
12:30:53 EDT
Aircraft began its descent from 23,000 feet (approximately 3 minutes 21 seconds from when the engine 1 oil pressure transitioned from 'No Warn' to 'Warn')
4
12:49:35 EDT
Weight on wheels main gear transitioned from 'Air' to 'Grnd'
4
Extracted by claude-sonnet-5; 12 of 13 stated events verified against the raw recorder data.