Boeing 757 incident near Atlanta, Georgia, September 6, 2018
On September 6, 2018 at about 3:32 am local time, a 1991 Boeing 757, registered N668DN, suffered minor damage in an incident during initial climb near Atlanta, Georgia. It was flown under scheduled airline rules (Part 121). No one was hurt. The weather was conditions the NTSB did not record.
The NTSB's probable cause their words, unchanged
A right engine turbine uncontainment resulting from failure of the high pressure turbine (HPT) lenticular seal due to a fatigue crack originating from an overheated region at a knife edge tip. Contributing to the failure was Pratt & Whitney’s decision to introduce the temperature-resistant knife-edge coating as a new-part number lenticular seal on an attrition basis without the option to recoat existing lenticular seals, which delayed implementation of the more durable seal material into the fleet.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 6, 2018 · about 3:32 am local time
- Place
- Atlanta, Georgia · map
- Type
- Incident
- Injuries
- No one was hurt.
- Weather
- conditions the NTSB did not record
- Aircraft
- Boeing 757 232, built 1991 · all 757s on the register
- Registration
- N668DN · registry record · serial 25141
- Damage
- Minor damage
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The high-pressure turbine (HPT) uncontainment was caused by the failure of a rotating seal located between the HPT 1st-stage (S1) disk and 2nd-stage (S2) hub (the lenticular seal). The lenticular seal outer structure separated from an inner brace piece and unwound, destroying the turbine. Seal fragments breached the turbine cases. A fragment traveled forward, destroying the HPT S1 blades and penetrating the S1 turbine nozzle assembly and combustor, damaging a fuel nozzle stem, and releasing fuel. The crack initiation site was destroyed by secondary damage. Although the failure mode was not determined, PW2000 engine lenticular seal cracks are a known failure associated with knife edge tip fatigue cracks that originate at the first or second knife edge tip and propagate down the knife edge pedestal to the barrel. Past root cause investigations determined that normal knife edge rub can cause local increases in knife edge tip temperature when the knife edge coating is worn and has begun to spall. Continued rub with degraded knife edge coating creates a heat affected zone at the knife edge tip that can lead to thermo-mechanical fatigue (TMF) and tip crack initiation. TMF is more likely to develop with second run seals matched with new honeycomb material. Review of the engine service records found that the failed lenticular seal was installed new during a 2008 overhaul when the engine had accumulated 61,385 time since new (TSN) and 25,462 cycles since new (CSN). The seal was visually inspected and reinstalled during a 2013 overhaul at 74,042 TSN and 31,701 CSN. During the 2013 shop visit, 40% of the lenticular seal land honeycomb surface was replaced. The lenticular seal chromium carbide knife edge coating was not renewed, so that the second-run lenticular seal knife edges with chromium carbide coating ran against new honeycomb material. The lenticular seal failed 6,460 cycles after the 2013 shop visit. An improved-design lenticular seal with the chromium carbide knife edge coating replaced with a more durable, temperature-resistant aluminum oxide coating was released by PW2000 SB 72-754 in 2011. The new-design seal was introduced as a part replacement on an attrition basis (use down-change part until exhausted).
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
- Engine shutdown during initial climb
- Loss of engine power (partial) during initial climb
- Uncontained engine failure during initial climb defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Design
The aircraft
- Maximum gross weight: 248,020 lb
- Landing gear: fixed
- Engine 1: Pratt & Whitney PW2037 (turbofan); 0 hours total
- Engine 2: Pratt & Whitney PW2037 (turbofan); 0 hours total
- Operator: Delta Air Lines
The flight
- Departed from: Atlanta GA
- Destination: Orlando FL
Weather at the time
- Light: not reported
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Documents from the investigation the NTSB's docket: the evidence folder behind the report
7 documents, released by the NTSB on April 5, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Powerplants Group Chair's Factual Report | PDF, 29 pages | View Download |
| 2 | Airworthiness Directive 2021-14-13 | PDF, 5 pages | View Download |
| 3 | Party Form, Boeing, Dan Marcotte | PDF, 2 pages | View Download |
| 4 | Party Form, P&w, Jeff Strausbaugh | PDF, 2 pages | View Download |
| 5 | Party Form - Zabawa | PDF, 2 pages | View Download |
| 6 | Party Form - Koza | PDF, 2 pages | View Download |
| 7 | Party Form - Dal Taylor Smith | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.