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ASN Wikibase Occurrence # 41045
Last updated: 30 November 2021
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Date:28-JUL-1983
Time:12:03
Type:Silhouette image of generic FH11 model; specific model in this crash may look slightly different
Fairchild Hiller FH-1100
Owner/operator:Hiller Aviation
Registration: N450FH
MSN: 215
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Porterville, CA -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Unknown
Departure airport:
Destination airport:
Investigating agency: NTSB
Narrative:
ON 7/27/83, MILD MAST BUMPING OCCURRED DURING A PUSHOVER MANEUVER WHILE A HILLER FH-1100 WAS ON A FLT TO CERTIFY NEW ROTOR BLADES. PRIOR TO THE INCIDENT, THE HELICOPTER WAS ACCELERATED TO 90 MPH. THIS WAS FOLLOWED BY A PULL-UP & DECELERATION TO 80 MPH, THEN THE PUSHOVER WAS INITIATED. THE HELICOPTER REPORTEDLY ROLLED SHARPLY TO THE RIGHT & PITCHEDNOSE DOWN WITH SOME YAW TO THE RIGHT. RECOVERY WAS MADE WITH LEFT CYCLIC; HOWEVER, DIRECTIONAL CONTROL WAS LOST BEFORE RECOVERY & MILD MAST BUMPING. ON 7/28/83, FH-1100, N450FH, A STANDARD PRODUCTION MODEL, WAS FLOWN TO EXPLORE THE PHENOMENON. AFTER 2 PUSHOVERS WITH INCREASING SEVERITY, IN WHICH CONTROL WAS RETAINED, THE PLT ATTEMPTED A REPETITION OF THE PREVIOUS DAY'S MANEUVER. WITNESSES OBSERVERVED THE HELICOPTER ROLL & YAW TO THE RIGHT & PITCH DOWN AS IT BEGAN TO BREAK UP, THEN BURN & CRASH. AN EXAM REVEALED THE MAIN ROTOR BLADES SEPARATED AFTER MAST BUMPING & MAST FAILURE OCCURRED. THERE WAS EVIDENCE THE PLT MIGHT NOT HAVE BEEN CURRENT IN TEETERING ROTOR SYSTEMS & RECOVERY FROM LOW G ROLLS. CAUSE:

Sources:

NTSB: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001214X43780


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:23 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
15-Jul-2018 12:59 Greg B Updated [Narrative]

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