WPR12LA138

NTSB accident investigation · Raven Industries S-66A · Avra Valley, AZ · March 16, 2012

Accident · Minor injuriesLimited investigationFinal report
Date
March 16, 2012, 08:00 local (15:00 UTC)
Place
Avra Valley, AZ
Injuries
3 minor, 6 uninjured
Damage
Substantial damage
Phase of flight
Approach
Aircraft
N57194Raven Industries S-66A
Defining event
Approach-VFR pattern final: Collision during takeoff/land
Weather
Visual (VMC) · Day
Status
Completed · report August 29, 2013
Report
Approved by Office Director
NTSB office
Western Pacific Region
Parties
Federal Aviation Administration
FAA report
20120316004789A
Case key
83146

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

The pilot's improper decision to partially open the balloon's vent before clearing a power line while landing, which resulted in the balloon descending too soon and contacting the power line.

Findings · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Performance/control parameters: descent/approach/glide pathAircraft › Aircraft oper/perf/capability · Not attained/maintainedRaven Industries S-66A: 1 caseAll aircraft: 809 casesProbable cause
Object/animal/substance: wireEnvironmental issues › Physical environment · Not specifiedRaven Industries S-66A: 1 caseAll aircraft: 588 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

Analysis

The pilot reported that the balloon was traveling 5 to 7 knots west toward a road oriented north-south with a power line running along the east side of the road. Beyond the power line and road was a large area of open desert where the pilot planned to land. When the balloon was about 100 yards from the lines at an altitude of about 300 feet above ground level, the pilot began setting the balloon up for landing by cracking open the vent-top of the envelope. The pilot operated one of the two burners to compensate for the expected loss of lift from the partly open top; however, the balloon began a slow descent instead of maintaining altitude, and the descent rate seemed to accelerate. In response, the pilot operated both burners and looked up at the top of the balloon, which he found was over a third open instead of the expected 2- to 3-foot crack. Realizing that the balloon’s glidepath would now result in the basket impacting the upper wire of the power line, the pilot decided to fully open the top of the balloon and land short of the power line. The balloon descended and impacted the power line wires with the basket suspension cables contacting more than one wire, which resulted in electrical arcing. The envelope folded over the wires, and the basket came to rest on the ground. The pilot stated that the accident could have been prevented by initiating the set-up for landing only after crossing the last obstacle before the landing area.

Factual narrative

On March 16, 2012, about 0800 mountain standard time, a Raven Industries, Inc., S-66A balloon, N57194, was substantially damaged when its envelope contacted electrical transmission lines during landing near Avra Valley, Arizona. The commercial pilot and two passengers received minor injuries, and the other six passengers were not injured. The balloon was registered to an individual, and doing business as Southern Arizona Balloon Excursions, under the provisions of 14 Code of Federal Regulations Part 91. A flight plan had not been filed for the local area sightseeing flight, which had originated from Marana, Arizona, about 0630. Visual meteorological conditions prevailed at the time of the accident. The pilot reported that the balloon was traveling west at a speed of 5 to 7 knots towards a road oriented north-south with a power line running along the east side of the road. Beyond the power line and road was a large area of open desert where the pilot planned to land. When the balloon was about 100 yards from the lines at an altitude of about 300 feet above ground level (agl), he began setting the balloon up for landing by “cracking open the vent-top of the envelope to set up a “heavy” condition for landing.” The pilot operated one of the two burners to compensate for the loss of lift from the partly open top; however, the balloon began a slow descent instead of maintaining altitude, and the descent rate seemed to accelerate. In response, the pilot operated both burners and looked up at the top of the balloon, which he found was “over a third open instead of the expected 2-3 foot opening.” Realizing that the balloon’s glide path would now result in the basket impacting the upper wire of the power line, he decided to fully open the top of the balloon and land short of the power line. The balloon descended and impacted the power line wires with the basket suspension cables contacting more than one wire resulting in electrical arcing. Pieces of burning balloon envelope material rained down into the basket. The envelope folded over the wires, and the basket came to rest on the ground. Three suspension cables were separated and several envelope panels were damaged. In the section of the National Transportation Safety Board Pilot/Operator Aircraft Accident Report titled “Recommendation (How could this accident/incident have been prevented?),” the pilot stated, “when operating LTA [lighter than air] aircraft initiate set-up for landing sequence only after crossing last obstacle prior to landing field/area.”

Aircraft

Registration
N57194
Reported as
Raven Industries S-66A
Category
Balloon
Serial number
S66A-115
Airframe hours
336
Damage
Substantial damage
Fire
On-Ground
Flight
Other work use · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · September 27, 2011
Departed
AVQ · Marana, AZ
Destination
Avra Valley, AZ

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
62
Injuries
None
Certificate
Commercial
Medical
Class 3, Without waivers/limitations
Last flight review
April 14, 2010
Flight hours
2,280 total · 10 in the last 90 days · 3 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
100° at 5 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
55 °F, dew point 14 °F
Altimeter
30.03 inHg
Observed at
RYN, 20 nm away

Docket · 5

The files NTSB released with the investigation on June 24, 2013, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.1 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.