Wednesday, September 16, 2020

Bell 407, N489DM: Incident occurred September 15, 2020 in Fort Worth, Texas

Federal Aviation Administration / Flight Standards District Office; North Texas

Rotorcraft during practice autorotation, main rotor struck the tail boom.

Chaparral Air Group

https://registry.faa.gov/N489DM

Date: 15-SEP-20
Time: 22:20:00Z
Regis#: N489DM
Aircraft Make: BELL
Aircraft Model: 407
Event Type: INCIDENT
Highest Injury: NONE
Aircraft Missing: No
Damage: UNKNOWN
Activity: INSTRUCTION
Flight Phase: UNKNOWN (UNK)
Operation: 91
City: FORT WORTH
State: TEXAS

3 comments:

  1. How does that happen that the main rotor strikes the tail boom? Do the blades flex that much?

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  2. Yes, hard landing and low rotor rpm in autorotation practice often gives a tail strike. Lots of writings about that can be found online.

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  3. Rotor blades are very flexible by design and for good reason: as they rotate their speed of rotation (lift and forward velocity mandates by the pilot) requires more or less lift depending on needs of the pilot. The blades droop while parked for this reason. Aircraft wings also flex for the same reason but at a lot less extreme...unless you are a 787 passenger and see the wingtip from your window bend up above eye level. So point being, if enough down force is exerted on them, they will bend down enough to strike the tail boom as they have in decades of rotorcraft autorotate accidents.

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