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ASN Wikibase Occurrence # 153590
Last updated: 15 January 2020
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Date:12-OCT-2009
Time:11:00
Type:Silhouette image of generic MD60 model; specific model in this crash may look slightly different
McDonnell Douglas MD 600N
Owner/operator:Department of Homeland Security
Registration: N613BP
C/n / msn: RN045
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Gillespie Field (SEE), San Diego, CA -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Unknown
Departure airport:San Diego, CA (SDM)
Destination airport:San Diego, CA (SEE)
Investigating agency: NTSB
Narrative:
According to the pilot-in-command (PIC), he was performing autorotations at the lower part of the main rotor rpm green arc in part due to weight considerations. Upon entering the accident autorotation, he maintained an airspeed between 85-90 knots in the hope that extra speed would allow a more aggressive deceleration flare prior to touchdown, which should in turn further slow the rate of descent and forward speed. The helicopter's rate of descent was high, and as the PIC turned the helicopter onto the runway heading it was apparent to him that the rate of descent was excessive and that he was too low to execute either a proper deceleration flare or perform a power recovery. He attempted to level the helicopter as much as possible prior to impact to minimize the damage to the helicopter and prevent injury. The helicopter landed hard with the left skid contacting the runway first. The left skid collapsed, damaging the outboard landing gear damper attachment structure. The helicopter slid about 100 yards before coming to a stop. According to the manufacturer, the main rotor rpm range is 90 percent to 106.4 percent. At the helicopter's weight and the density altitude on the day of the accident, the main rotor rpm during the autorotation should have been above the 106.4 percent limit (red line), requiring the pilot to increase collective pitch to maintain the rotor rpm within limits. Performing autorotations at the lower part of the green arc provides less availability of rotor energy to perform an autorotation landing. The pilot should have recognized that he was not achieving the required main rotor rpm for the autorotations and terminated the maneuvers. The helicopter was within weight and balance limits.
Probable Cause: The pilot's failure to maintain adequate main rotor rpm during an autorotation, which resulted in a hard landing.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20091013X04846&key=1


Revision history:

Date/timeContributorUpdates
27-Feb-2013 10:59 TB Added
23-Sep-2014 20:11 harro Updated [Narrative]
21-Dec-2016 19:28 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
02-Dec-2017 17:05 ASN Update Bot Updated [Operator, Other fatalities, Nature, Departure airport, Destination airport, Source, Narrative]

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