Boeing 757-222 N526UA

Summary

On 26 September 2011 at about 22:37 local time, a Boeing 757-222 registered N526UA, operated by UNITED AIRlNES INC, was involved in an incident near Denver, Colorado, United States. 185 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

26 September 2011 at 22:37

Classification

Incident

Location

Denver, Colorado, United States

Nearest airport

Denver International (DEN)

Coordinates

39.7498, -105.0000

Aircraft

Boeing 757-222

Registration

N526UA

Category

Airplane

Engines

2

Operator

UNITED AIRlNES INC

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Chicago → Denver

Aircraft damage

Minor

NTSB number

ENG11IA051

Nobody was injured.

**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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.