LAX07CA036

NTSB accident investigation · Burkhart Grob Flugzeugbau G103 Twin Astir · Tucson, AZ · November 15, 2006

Accident · No injuriesData collectionFinal report
Date
November 15, 2006, 14:37 local (21:37 UTC)
Place
Tucson, AZ
Injuries
1 uninjured
Damage
Substantial damage
Phase of flight
Landing
Aircraft
N4115MBurkhart Grob Flugzeugbau G103 Twin Astir
Weather
Visual (VMC) · Day
Status
Completed · report March 26, 2007
Report
Approved by Office Director
Parties
Federal Aviation Administration
FAA report
20061115027229A
Case key
64892

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

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Probable cause

The pilot's improper use of the spoilers during the landing flare, which resulted in a hard landing, and his inadequate bounced landing recovery technique.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Hard landingLanding - flare/touchdown
Spoiler retraction - improper use ofPilot in commandCause
Recovery from bounced landing - inadequatePilot in commandCause
Terrain condition - runway

Analysis

The glider pilot reported he was attempting to land the glider further down the runway than usual. He stated he added 1/2 spoilers and flared about 10 feet above the runway. He retracted the spoilers, and added them again when he was further down, and about 5 feet above the runway. At the second spoiler application, the glider immediately fell to the runway, hitting hard and bouncing. The glider bounced another two or three times, coming to rest after the tail section separated. The pilot stated that there were no pre accident mechanical or flight control problems with the glider.

Factual narrative

On November 15, 2006, at 1437 mountain standard time, a Burkhart Grob Flugzeugbau G103 Twin Astir glider, N4115M, landed hard at El Tiro Gliderport (AZ67), Tucson, Arizona, and porpoised on runway 8R before coming to a stop. Tucson Soaring Club operated the rental glider under the provisions of 14 CFR Part 91. The private glider pilot, the sole occupant, was not injured. The tail section of the glider separated forward of the vertical stabilizer and the horizontal stabilizer sustained damage. Visual meteorological conditions prevailed for the local area flight that departed about 1430. No flight plan had been filed.

According to the pilot's written statement, he had conducted two flights on the day of the accident. He noted clear sky conditions, and a slight north crosswind between 3 and 5 knots. The first flight was uneventful, except that he was only able to stay aloft for 16 minutes due to low thermal activity. He made the approach at 60 knots, and the landing was normal.

On the second flight, the accident flight, he flew the pattern with the intent of landing long so that he could put the glider away for the day, as it was not scheduled for additional flights. He made the approach at 60 knots, added 1/2 spoilers, and flared about 10 feet above the ground. At that point, he closed the spoilers so that the touchdown point would be longer than normal. The glider floated about 5 feet above the runway and he applied 1/2 spoilers so that the glider would touch down. The glider immediately dropped and landed hard, which resulted in it bouncing back into the air.

The pilot stated that he held the stick in a fixed position with the wings level, thinking that the glider would float down to the runway and land, with the potential of bouncing 2 or 3 more times. He stated that the glider bounced 2 or 3 more times; however, each touchdown was harder than the previous time. Upon exiting the glider, he noted that the tail section had separated from the fuselage. The pilot stated that there were no mechanical or flight control problems with the glider prior to the accident.

Aircraft

Registration
N4115M
Reported as
Burkhart Grob Flugzeugbau G103 Twin Astir
Category
Glider
Serial number
3799K
Engine
Damage
Substantial damage
Flight
Personal · Part 91
Registered owner
Tucson Soaring Club
Airworthiness certificate
Standard, Normal
Departed
AZ67 · Tucson, AZ
Destination
AZ67 · Tucson, AZ
Airport
AZ67 · El Tiro Gliderport, runway 08R, 5,000 × 100 ft, asphalt

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
Certificate
Private
Flight hours
63 total · 38 in this make and model

Weather

Conditions
Visual (VMC) · Day
Visibility
30 statute miles
Lowest ceiling
None
Temperature
82 °F, dew point 50 °F
Altimeter
29.96 inHg
Observed at
AVQ

FAA reports on this event · 1

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