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ASN Wikibase Occurrence # 35504
Last updated: 5 April 2019
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Date:28-JUN-1994
Time:19:54
Type:Silhouette image of generic SS2P model; specific model in this crash may look slightly different
Rockwell S-2R Thrush Commander
Owner/operator:Tri Air
Registration: N4230X
C/n / msn: 1996R
Fatalities:Fatalities: 1 / Occupants: 1
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Category:Accident
Location:Firebaugh, CA -   United States of America
Phase: Manoeuvring (airshow, firefighting, ag.ops.)
Nature:Agricultural
Departure airport:(Q49)
Destination airport:(Q49)
Investigating agency: NTSB
Narrative:
THE AIRPLANE WAS LOADED WITH 2,000 POUNDS OF POWDERED SULFUR. A WITNESS SAID THE AIRPLANE HAD JUST COMPLETED A SPRAY RUN, AND BEGAN A LEFT TURN TO MAKE WHAT THE WITNESS ASSUMED WAS A SOUTHBOUND RUN ON THE FIELD. FLAMES WERE SEEN ON THE BOTTOM OF THE AIRPLANE IN THE VICINITY OF THE DISPENSER APPARATUS. THE AIRPLANE DESCENDED A LITTLE, STARTED TO CLIMB AGAIN, THEN SUDDENLY NOSED OVER AND DOVE VERTICALLY INTO THE GROUND. INFLIGHT AND POSTCRASH FIRE HAD TOTALLY CONSUMED ALL OF THE NON-STEEL AIRCRAFT COMPONENTS, AND THE FIRE SEEMED TO HAVE BEEN MORE INTENSE IN THE AREA OF THE CHEMICAL HOPPER AND SPRAY APPARATUS. THE CHEMICAL MANUFACTURER SAID THE POWDERED SULFUR DUST USED IN AG OPERATIONS IS A MODERATE FIRE HAZARD ACCORDING TO NFPA CRITERIA. THE COMPOUND HAS A FLASH POINT OF 374 DEG F, YET STUDIES SHOW THAT CLOUDS OF DUST MAY IGNITE AT IGNITION TEMPS OF 190 DEG IN DENSITY LIMITS OF LESS THAN 0.1 OUNCES PER CUBIC FOOT. CAUSE: THE PILOT'S LOSS OF AIRCRAFT CONTROL AS A RESULT OF INCAPACITATION FROM AN IN-FLIGHT SULFUR FIRE.

Sources:

NTSB: https://www.ntsb.gov/ntsb/brief.asp?ev_id=20001206X01583


Revision history:

Date/timeContributorUpdates
24-Oct-2008 10:30 ASN archive Added
21-Dec-2016 19:22 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]

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