Lockheed 382G accident near Iliamna, Alaska, February 12, 2016
On February 12, 2016 at about 4:45 pm local time, a 1975 Lockheed 382G, registered N401LC, was substantially damaged in an accident during enroute (cruise) near Iliamna, Alaska. It was flown under scheduled airline rules (Part 121). No one was hurt; 5 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The fatigue failure of the forward pressure bulkhead canted web that originated from stress corrosion cracking areas. Contributing to the failure were inspection procedures and intervals inadequate to identify the crack.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 12, 2016 · about 4:45 pm local time
- Place
- Iliamna, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 5 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Lockheed 382G, built 1975 · all 382Gs on the register
- Registration
- N401LC · registry record · serial 4606
- Damage
- Substantial damage
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The airplane suffered a rupture in the forward pressure bulkhead canted web causing a rapid depressurization during flight. The crew declared an emergency and diverted to the nearest airport where they landed safely. The accident airplane was manufactured in 1975 and had accumulated 35,421 flight cycles. Examination of the fractured canted web revealed multiple fatigue cracks that initiated at the forward and aft surfaces of the web adjacent to a vertical line of rivets at the airplane centerline. The fatigue cracking from the aft face propagated through 85%-90% of the thickness and the fatigue cracking from the forward face propagated through the remaining thickness. The fatigue cracking was present near 21 consecutive rivet holes. Dark staining determined to be aluminum oxide was noted on the mating fracture faces in areas that contained the larger fatigue cracks indicating the larger fatigue cracks were present for some time prior to the accident flight. The aluminum oxide contained trace evidence of chlorine. Chlorides are known contaminants that promote corrosion in aluminum alloys. The investigation did not determine the source of the chlorine contamination. Detailed examination of the fatigue crack initiation sites revealed the presence of isolated areas that contained evidence of intergranular cracking. Intergranular cracking and chlorine contamination typically are associated with stress corrosion cracking in aluminum alloys. There were no material discrepancies noted on the fractured web. Areas between fatigue cracks and at the upper and lower ends were due to overstress separation. A fatigue crack striation study indicated that the cracks likely initiated about 5,000 cycles prior to the accident flight. The manufacturer released a Service Bulletin based on the findings of the investigation to provide more detailed instructions and updated intervals to inspect for cracking of the forward pressure bulkhead canted web.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Aircraft structural failure during enroute (cruise) defining event
The NTSB's findings
- cause Aircraft › Aircraft structures › Fuselage › Bulkheads (main fuselage) › Fatigue/wear/corrosion
- factor Aircraft › Aircraft handling/service › Maintenance/inspections › Scheduled maint checks › Related maintenance info
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 20,528 hours in all; 5,826 in this make and model
- Last flight review: September 17, 2015
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Pilot (unmanned)
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 25,503 hours in all; 8,522 in this make and model
- Last flight review: July 21, 2015
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
Flight Engineer
- Certificate: flight engineer
- Flight time: 13,300 hours in all
- Seat: ctr
- Injury: no injuries
Other crew
- Seat: sngl
- Injury: no injuries
Other crew
- Seat: ctr
- Injury: no injuries
The aircraft
- Airframe total time: 55,393 hours
- Last inspection: continuous airworthiness programme, February 8, 2016
- Maximum gross weight: 155,000 lb
- Seats: 7
- Landing gear: retractable
- Engine 1: Allison 501-D22A (turboprop); 66,658 hours total
- Engine 2: Allison 501-D22A (turboprop); 33,027 hours total
- Engine 3: Allison 501-D22A (turboprop); 14,920 hours total
- Engine 4: Allison 501-D22A (turboprop); 30,619 hours total
- Operator: Lynden Air Cargo
The flight
- Departed from: BET Bethel AK
- Destination: EDF Anchorage AK
- Flight plan: IFR
- A second pilot was aboard
Weather at the time
- Light: dawn
- Wind: from 260° at 5 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 12,000 ft; a few clouds
- Temperature: 32°F (0°C), dew point 28°F (-2°C)
- Altimeter: 29.31 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 5 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N401LC the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.