Bell 525 accident near Italy, TX
On July 6, 2016, a Bell 525 (helicopter) was involved in an accident near Italy, TX. 2 people died. Damage to the aircraft: destroyed.
- Date
- July 6, 2016
- Place
- Italy, TX
- Aircraft
- Bell 525 · Helicopter
- Injuries
- 2 fatal, 0 serious, 0 minor
- Damage
- Destroyed
- Position
- 32.246°N, 96.920°W
- NTSB ID
- 20160706X42741
Official records · DCA16FA199
- Public docket: reports, statements and exhibits from the investigation
Air traffic control records
- ASR1801 - Use of Recording Devices During Experimental Flight Test Activities: Document (PDF), on ntsb.gov
NTSB summary
HISTORY OF FLIGHTOn July 6, 2016, about 1148 central daylight time, an experimental research and development Bell 525 helicopter, N525TA, broke up in flight and impacted terrain near Italy, Texas. The two test pilots received fatal injuries, and the helicopter was destroyed. The helicopter, which was owned by Bell Helicopter Textron, Inc., was being operated under the provisions of 14 Code of Federal Regulations (CFR) Part 91 as a developmental flight test. Visual meteorological conditions prevailed at the time of the accident. The flight originated from Arlington Municipal Airport, Arlington, Texas. About 0630 on the morning of the accident, the two test pilots, flight test engineers, and a chase helicopter flight crew briefed the planned flight. The brief detailed that the accident helicopter, accompanied by a chase helicopter, would proceed to the Arlington Initial Experimental Test Area (about 30 miles south of Arlington Municipal Airport) to perform the in-flight portion of the tests. The purpose of the flight was to evaluate engine loads at maximum continuous power, two-to-one-engine simulated engine failures, longitudinal roll oscillations, and run-on landings in the heavy, forward center-of-gravity configuration. The test card for the two-to-one-engine simulated engine failure detailed that the pilots would simulate the loss of engine power from one engine while keeping both engines operating by using one-engine-inoperative (OEI) special training mode software, which reduced the power output of both engines to represent the maximum power that can be produced by one
Probable cause
A severe vibration of the helicopter that led to the crew's inability to maintain sufficient rotor rotation speed (Nr), leading to excessive main rotor blade flapping, subsequent main rotor blade contact with the tail boom, and the resultant in-flight breakup. Contributing to the severity and sustainment of the vibration, which was not predicted during development, were (1) the collective biomecha
From Wikipedia
The 2016 Bell 525 Relentless prototype crash occurred during a test flight on July 6, 2016, near Italy, Texas, destroying the prototype Bell 525 Relentless helicopter and killing the two occupants. The helicopter broke up in flight while traveling about 229 mph (199 kn) at an altitude of about 2,000 feet (610 m); the main rotor contacted and severed the tail boom due to severe vertical oscillations. The crew were performing one engine inoperative (OEI) recovery testing; the test induced a scissors-mode vibration in the main rotor, which resulted in involuntary collective control input. The unintended biomechanical feedback loop exacerbated the vibration, until the rotor contacted the tail-boom.
The destruction of the prototype delayed type certification of the Bell 525 for a year and a filter was added to the collective input control to avoid recurrence of the biomechanical feedback.
Text from Wikipedia, “2016 Bell 525 Relentless prototype crash”, CC BY-SA 4.0; shortened to the introduction. Authors.
More accidents in TX
- Kubicek BB85, Jul 30, 2016
- Robertson C-414, Jul 29, 1982
- Textron Aviation B-300, Jun 30, 2019
- Beech B100, Nov 26, 1983
- Consolidated-Vultee PBY-6A, Oct 13, 1984
Browse: Texas · Bell aircraft
Source: NTSB aviation accident database (US government, public domain). Findings may be preliminary or later revised by the NTSB. Not a complete global record.
