Boeing 757-222 incident near Denver, Colorado, September 26, 2011
On September 26, 2011 at about 10:37 pm local time, a Boeing 757-222, registered N526UA, suffered minor damage in an incident during landing (landing roll) near Denver, Colorado (Denver International airport). It was flown under scheduled airline rules (Part 121). No one was hurt; 185 people were on board or involved.
The NTSB's probable cause their words, unchanged
**This probable cause was modified on 4/5/2012. Please see the public docket for this accident to view the original probable cause.** The initial damage to the fan blades was caused by the ingestion of a Red-Tailed Hawk that caused one or more fan blades to fracture, striking the fan case and causing it to bulge. The initial fan blade fragment release impacted and damaged other passing fan blades generating various sized blades fragments. Some of these blade fragments were propelled forward of the fan case by passing fan blades and were reingested, creating a cascading effect of collateral impact damage to the other fan blades, the fan case, and the inlet cowl.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 26, 2011 · about 10:37 pm local time
- Place
- Denver, Colorado · Denver International · map
- Type
- Incident
- Injuries
- No one was hurt; 185 people were on board or involved.
- Weather
- not recorded
- Aircraft
- Boeing 757-222 · all 757-222s on the register
- Registration
- N526UA · no longer on the register · serial 24994
- Damage
- Minor damage
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
On September 26, 2011, 1637 mountain daylight time, a Boeing B-757-222, registration number N526UA, operated by United Airlines (UAL) as flight 909, and powered by two Pratt & Whitney PW2037M turbofan engines, experienced a left engine (No. 1) bird strikeF following touchdown on runway 35R at the Denver International Airport (DEN), Denver, Colorado. According to the flightcrew, after initial touchdown and the application of full reverse thrust, two hawks were observed on the centerline of runway 35R and shortly thereafter impacts were felt on the fuselage. The airplane was towed to the gate using a tug where the passengers deplaned normally. The incident flight was a 14 CFR Part 121 domestic passenger flight from Chicago O’Hare Airport (ORD) to DEN. Examination of the airplane revealed only minor gouging of the fuselage while the No. 1 engine inlet cowl exhibited multiple impacts, gouges, and through-holes. Examination of the No. 1 engine revealed that all the fan blades were extensively damaged, three fractured transversely across the airfoil at or near the mid-span shroud, but no penetration or breaches were observed in any of the engine cases. The bird remains recovered within the No. 1 engine were identified as coming from a female Red-Tailed Hawk. An intact bird that struck the side of the No. 1 inlet was also identified as a Red-Tailed Hawk but was not sexed. Comparing the airplane and engine damage to the requirements for bird ingestion and engine debris containment at the time the engine and airplane were both certificated revealed that the engine complied with the bird ingestion and containment requirements set forth in Parts 33.77 and 33.19 and the airplane complied with the containment requirements set forth in Parts 25.903.
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
- Birdstrike during landing (landing roll) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Power plant › Engine cowling system › Damaged/degraded
- Aircraft › Aircraft power plant › Power plant › Engine cowling system › Capability exceeded
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Damaged/degraded
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Compressor section › Capability exceeded
- cause Environmental issues › Physical environment › Object/animal/substance › Animal(s)/bird(s) › Effect on equipment
The aircraft
- Seats: 178
- Landing gear: fixed
- Engine 1: P & W PW2037M (turbofan); 0 hours total
- Engine 2: P & W PW2040 (turbofan); 0 hours total
- Operator: United Airlnes INC
The flight
- Departed from: ORD Chicago IL
- Destination: DEN Denver CO
- Flight plan: VFR
- Runway 35R
- A second pilot was aboard
Weather at the time
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 4 | |||
| Flight crew | 2 | |||
| Passengers | 179 |
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 N526UA 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.