CEN12LA490

NTSB accident investigation · Smith Applebay Zuni II · Gregory, MI · July 29, 2012

Accident · Serious injuriesLimited investigationFinal report
Date
July 29, 2012, 13:43 local (17:43 UTC)
Place
Gregory, MI
Injuries
1 serious
Damage
Substantial damage
Phase of flight
Approach
Aircraft
N1ZVSmith Applebay Zuni II
Defining event
Approach-VFR pattern base: Aerodynamic stall/spin
Weather
Visual (VMC) · Day
Status
Completed · report July 30, 2014
Report
Approved by Office Director
NTSB office
Central Region
Parties
FAA Detroit FSDO
FAA report
20120729019399A
Case key
84491

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 glider pilot’s failure to maintain sufficient altitude and airspeed while turning to the base leg of the traffic pattern, which resulted in a stall/spin and impact with trees and terrain.

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: altitudeAircraft › Aircraft oper/perf/capability · Not attained/maintainedSmith Mike APPLEBAY ZUNI: 1 caseAll aircraft: 1,310 casesProbable cause
Performance/control parameters: airspeedAircraft › Aircraft oper/perf/capability · Not attained/maintainedSmith Mike APPLEBAY ZUNI: 1 caseAll aircraft: 1,681 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 takeoff and tow to 3,000 feet above ground level (agl) was normal. The pilot released the glider from the tow airplane about 2 miles northwest of the airport. He was unable to achieve the necessary lift, and, as the glider lost altitude, he started flying back toward the airport and proceeded toward the initial point for landing on the runway. As the pilot flew the glider on the downwind pattern leg, he realized that he was not going to be able to complete the traffic pattern. He attempted to clear the tree line that crossed the downwind leg, but the glider hit the trees and subsequently impacted terrain. A witness reported that the glider's altitude was about 125 to 150 feet agl when it was on the downwind leg and that its airspeed was too low. The witness added that the glider continued to slow as it turned to the base leg, at which point, the left wing stalled, and then the glider pitched down nearly vertical and completed about 1/2 spin before it disappeared behind the trees. A postaccident examination of the airframe revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

Factual narrative

On July 29, 2012, at 1343 eastern daylight time, an experimental Smith Applebay Zuni II glider, N1ZV, sustained substantial damage when it impacted trees and terrain while on the downwind leg to runway 36 at the Richmond Field Airport (69G), Gregory, Michigan. The pilot, the sole occupant, received serious injuries. The glider was registered to and operated by the pilot under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed for the local flight which originated from 69G at 1329. The pilot reported that he completed the pre-takeoff checklist, which included a positive control check of the flight controls. He reported that the takeoff and tow to 3,000 feet above ground level (agl) was normal. The pilot released the glider from the tow airplane at 3,000 feet agl about 2 miles northwest of 69G. The pilot was unable to find the necessary lift, and as the glider lost altitude, he started flying back toward the airport. Still not finding the needed lift, he proceeded toward the initial point for landing on runway 36. As the pilot flew the downwind pattern leg, he realized that he was not going to be able to complete the pattern. He attempted to clear the tree line that crossed the downwind leg, but the glider hit the trees and subsequently impacted the terrain. A witness located at the airport reported that he observed the glider on the downwind leg. He reported that the glider's altitude was low – about 125 to 150 feet agl, and it was in close to the airport and flying "somewhat slowly." The glider seemed to slow down even more as it began to turn to the base leg. He reported that the left wing stalled and the glider pitched down nearly vertical. It completed about 1/2 spin before it disappeared behind the trees about 2,000 feet away. Another witness at the airport also reported that the glider was too low on the downwind leg. He reported that the glider went down as it turned to shorten the pattern. A Federal Aviation Administration inspector examined the glider wreckage. Flight control cable continuity was confirmed from the flight controls to their respective attach points on the flight control surfaces. The inspection of the glider did not reveal any evidence of pre-impact failure or malfunction.

Aircraft

Registration
N1ZV
Reported as
Smith Applebay Zuni II
Category
Glider
Serial number
30
Airframe hours
184
Damage
Substantial damage
Flight
Personal · Part 91
Operator
Wasilewski Stephen G
Registered owner
Wasilewski Stephen G
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Condition · May 1, 2012
Departed
69G · Gregory, MI
Destination
69G · Gregory, MI
Airport
69G · Richmond Field Airport, runway 36, 2,471 × 100 ft, grass/turf

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
66
Injuries
Serious
Certificate
Commercial
Last flight review
April 12, 2012
Seat
Single
Flight hours
163 total · 15 in this make and model · 130 as pilot in command · 3 in the last 90 days · 2 in the last 30 days

Weather

Conditions
Visual (VMC) · Day
Wind
Variable at 4 knots
Visibility
10 statute miles
Lowest ceiling
20,000 ft broken
Temperature
82 °F, dew point 50 °F
Altimeter
30.09 inHg
Observed at
LAN, 26 nm away

Docket · 2

The files NTSB released with the investigation on June 26, 2014, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.7 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.