Aviation Accident Summaries

Aviation Accident Summary CEN12FA378

Wallis, TX, USA

Aircraft #1

N6388V

IAR BRASOV IS-28B2

Analysis

A witness reported that, before launch, the pilot installed the tail dolly on the glider, and the ground crew then assisted him pull the glider near the normal launch position about midfield. Another witness reported that the pilot then assisted the passenger and the lapchild into the front seat of the glider and ensured that the restraints were properly latched and snug. The pilot then got in the rear seat, and he secured his own lap belt and shoulder straps. Several witnesses noticed that, after takeoff, the tail dolly was still attached to the glider, and the glider operations dispatcher made a radio call to "abort...abort...abort." The takeoff continued, and several witnesses observed both the tow plane and the glider lift off normally. When the tow plane was about 50 feet above ground level (agl), the glider suddenly pitched nose up about 45 degrees, and the tow plane disconnected from the glider and turned left. The glider subsequently turned right and continued to climb steeply until it was about 150 to 200 feet agl. The glider then began what appeared to be a controlled left turn with the nose level. While the glider was turning, witnesses saw it suddenly pitch nose down and descend. Wreckage evidence showed that the glider impacted terrain at a 30- to 45-degree nose-down angle. The glider's rapid, near-vertical descent is consistent with the pilot's loss of control of the glider because of an aerodynamic stall. An on-scene examination of the wreckage revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. Two other pilots reported that they had previously inadvertently made takeoffs in the same model glider with the tail dolly still attached. Both of them reported that the flight characteristics did not change in that condition. A postaccident weight and balance calculation showed that the glider's weight and balance were still within the allowable range with the addition of the tail dolly. At the time of the accident, the pilot had cardiac hypertrophy and severe coronary artery disease. His physician had examined him 3 days before the accident and had ordered several tests. It is likely that, if the pilot had undergone a stress test, he would have failed it, and further evaluation would likely have led to a coronary artery bypass graft operation in the following few days. The pilot's wife reported that the pilot had spent the day of the accident engaging in strenuous activity, including teaching students and moving the glider around. Given the extent of coronary artery disease found on the pilot's autopsy, it is likely that the pilot's sudden awareness of the emergency situation (takeoff with the tail dolly attached) and physical exertion before the flight led to an acute coronary event and that this event contributed to his loss of control.

Factual Information

HISTORY OF FLIGHTOn June 17, 2012, about 1655 central daylight time, an IAR Brasov model IS-28B2 glider, N6388V, impacted terrain after a loss of control while maneuvering near the GHSA-Wallis Gliderport (TE71), Wallis, Texas. The pilot, an adult non-pilot passenger, and a lap child were fatally injured. The glider was substantially damaged. The glider was registered to and operated by Greater Houston Soaring Association under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions prevailed and no flight plan was filed. At the time of the accident the glider was departing from TE71 for the local flight. Prior to launch, the pilot installed the tail dolly on the glider, and the ground crew assisted him to pull it up close to the normal launch position at about mid-field. The pilot then assisted the passenger and the lap child into the glider. After the adult passenger was seated in the front seat the lap child was then placed, forward facing, on the lap of the passenger. The lap belt was secured across the lap of the lap child, and the shoulder straps were placed over the shoulders of both persons. The pilot, standing next to the front cockpit seat, assisted them in securing their seatbelts and shoulder straps and appeared to take great care to ensure everything was properly latched and snug. Then the pilot got in the rear seat and he secured his own lap belt and shoulder straps without assistance. After a normal hook up on the ground, the tow pilot got a "tail waggle" from the glider and he started a normal takeoff to the south on runway 18. As the take-off roll began several persons noticed that the tail dolly was attached to the glider and a radio call was made to "abort … abort … abort". The take-off continued and several witnesses observed a normal lift off by both the tow plane and the glider. The tow pilot reported he had lifted off at 65 mph and was about 25 feet above ground level (agl) when he heard a radio call to abort. When he was about 50 feet agl and about over the south end of the runway his tow plane was beginning to be pulled into a 10 to 15 degree nose down attitude. As the tow pilot was reaching to pull the towline release he could feel that the rope had already released and the nose of the tow plane then "whipped" up and to the left. Several witnesses reported that during the launch they saw the glider suddenly pitch nose up and climb to the right. One witness estimated the glider was about 75 feet agl when the tow plane banked sharply to the left and he saw the glider "rocket up" behind the tow plane as if it were on a winch style launch. He estimated that the glider was climbing at a 45 degree slope. The glider turned to the right and continued to climb steeply until it was about 150 to 200 feet agl. The glider then began what appeared to be a controlled turn to the left with nose level. At around 45 to 90 degrees into the 180 degrees needed to return to the field, witnesses saw the glider suddenly pitch nose down and descend. PERSONNEL INFORMATIONThe pilot, age 68, held an Federal Aviation Administration (FAA) commercial pilot certificate with a rating for glider only, which was issued on November 1, 1987. He also held an FAA flight instructor certificate – glider only which was initially issued on June 1, 1991. His most recent renewal issuance of that flight instructor certificate was on March 21, 2011. Based on a review of portions of the pilot's glider logbook number four, estimates from family members and friends, and FAA registry records; the pilot's flight experience in all aircraft was estimated as a total of 775 hours. Records showed that 15 of those hours were as a pilot in single engine airplanes and a total of 760 of those hours were in gliders. His experience as a flight instructor was estimated as a total of 390 hours. A logbook entry in June, 2010 showed that he then had logged 1,593 flights in gliders. An endorsement in the pilot's logbook showed a flight review was completed on March 25, 2012. AIRCRAFT INFORMATIONThe model IS-28B glider, serial number 364, was manufactured by IAR Brasov in 1999, and had been registered to the owner since 2000. It was a 2-place all-metal glider of conventional design with a T-tail, tandem landing gear with a retractable main wheel, flaps, TOST style release mechanisms, and spoilers which were mounted on the top and bottom of both wings. The cockpit was equipped with tandem pilot seats in front and rear. Each of the seats was fitted with 4-point restraint systems which had a two strap lap belt and a two strap shoulder harness system which fastened to the buckle at the center of the lap belt. The glider was also equipped with a removable tail dolly, intended for ground handling use. The hinged cuff, of composite material was painted red and had a fully swiveling wheel on the bottom. The tail dolly, which weighed about 11 pounds, could be clamped onto the rear of the empennage just forward of the bottom leading edge of the vertical fin. A review of the original maintenance records showed that the glider had its first flight in 1999, and had been registered to the current owner since 2000. Maintenance record entries showed that an annual inspection was completed on February 22, 2012, at an aircraft total time of 1,156 hours and 20 minutes; and then had a total of 2,465 flights since new. The operator estimated that the glider had been operated for about 22 hours since the annual inspection. METEOROLOGICAL INFORMATIONThe closest official weather reporting station was at Sugar Land Regional Airport (SGR), Sugar Land, Texas, located 19 miles east from the accident location, At 1653, the automated weather observation station at SGR reported wind from 120 degrees at 6 knots; broken clouds at 7,000 feet, temperature 31 degrees Celsius (C), dew point temperature 19 degrees C, and an altimeter setting of 29.88 inches of Mercury. AIRPORT INFORMATIONThe model IS-28B glider, serial number 364, was manufactured by IAR Brasov in 1999, and had been registered to the owner since 2000. It was a 2-place all-metal glider of conventional design with a T-tail, tandem landing gear with a retractable main wheel, flaps, TOST style release mechanisms, and spoilers which were mounted on the top and bottom of both wings. The cockpit was equipped with tandem pilot seats in front and rear. Each of the seats was fitted with 4-point restraint systems which had a two strap lap belt and a two strap shoulder harness system which fastened to the buckle at the center of the lap belt. The glider was also equipped with a removable tail dolly, intended for ground handling use. The hinged cuff, of composite material was painted red and had a fully swiveling wheel on the bottom. The tail dolly, which weighed about 11 pounds, could be clamped onto the rear of the empennage just forward of the bottom leading edge of the vertical fin. A review of the original maintenance records showed that the glider had its first flight in 1999, and had been registered to the current owner since 2000. Maintenance record entries showed that an annual inspection was completed on February 22, 2012, at an aircraft total time of 1,156 hours and 20 minutes; and then had a total of 2,465 flights since new. The operator estimated that the glider had been operated for about 22 hours since the annual inspection. WRECKAGE AND IMPACT INFORMATIONThe impact location was about 3,500 feet south of the take-off position at TE71, and about 400 feet west of the extended runway centerline. The glider came to rest upright in a slightly nose down attitude in 3-foot tall cotton in a flat farm field. A ground impact crater corresponding to the nose impact was found under the nose of the glider. The nose and front cockpit section showed impact crushing damage and were bent slightly to the right and bent up about 45 degrees from the horizontal. The aft fuselage and empennage were oriented to about 160 degrees. There was a ground impact mark oriented to about 230 degrees which corresponded to the leading edge impact damage on the right wing which was oriented to about 260 degrees from the fuselage. The outer portion of the left wing was bent aft about 40 from left wing. The leading edges of both wings had impact crushing damage of about 30 to 40 degrees from the horizontal. The landing gear was fully extended. Both flaps were in the Flaps 1 position. All four spoilers were fully extended. A red tail dolly remained attached to the rear of the empennage. The empennage was intact and showed little damage. The tail surfaces showed little damage except for scorpion tail bending damage which was observed at the lower forward portion of the vertical fin. Except for impact separation damage, control continuity was mostly confirmed for the ailerons, rudder, flaps, spoilers, and trim control. Flight control continuity could not be confirmed to the front cockpit because of impact damage. The wing to fuselage junction bolt was observed normally connected. All L'Hoteiller connections were observed normally connected. Both flight control sticks were impact separated at the bottom of the stick. The glass was shattered in the front cockpit airspeed indicator and the needle was missing. The needle in the rear cockpit airspeed indicator was observed at 100 knots. Postaccident testing of the airspeed indicators was not possible because of extensive impact damage. The Kollsman window on both altimeters was observed set to 29.92. The variometer in the rear cockpit indicated a plus 2.5. The G-meter in the front cockpit indicated 0 G positive and minus 2 G. In the front cockpit, the 4-point restraint system buckle assembly was observed still connected. Both lap belt attach fittings were observed impact separated from their attach points. Both shoulder harness belts were intact and the attach fittings were still connected the cross frame, however the cross frame was completely separated from its attach points. Both shoulder harness belts were intact and the attach fittings were still connected to the buckle on the lap belt. In the rear cockpit, the 4-point restraint system buckle assembly was observed still connected. Both lap belt attach fittings were observed impact separated from their attach points. Both shoulder harness belts were still attached to the buckle on the lap belt. The right shoulder harness belt was observed separated where the webbing had been cleanly cut similar to a scissor cut. The cockpit canopy Plexiglas was shattered and all portions of the canopy frame were observed adjacent to the main wreckage. Both right side canopy hinges were impact separated. The rear canopy latch was in the closed position and the front canopy latch was in the half open position. Both canopy latch receptacles were intact, but the airframe structure into which they were installed was impact damaged. The canopy jettison handle was observed closed. Continuity of the tow release cable was confirmed from the front cockpit to the front TOST release mechanism. The undamaged towline was found in the cotton field about 275 feet south of the south end of runway 18. The towline was retrieved, and attached to the front TOST release mechanism on the glider. Postaccident testing showed that it functioned normally. The towline was then attached to the TOST release mechanism on the rear of the tow plane and postaccident testing showed that it functioned normally. The on-scene examination of the wreckage revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. ADDITIONAL INFORMATIONAccording to the FAA-H-8083-13A, Glider Flying Handbook: (page 8-11) If an inadvertent release, towline break, or a signal to release from the tow plane occurs at a point at which the glider has insufficient runway directly ahead and has insufficient altitude (200 feet above ground level AGL) to make a safe turn, the best course of action is to land the glider ahead ... If the inadvertent release, towline break, or signal to release from the tow plane occurs after the towplane and glider are airborne, and the glider possesses sufficient altitude to make a course reversal … a minimum altitude of 200 feet above ground level is required to complete this maneuver safely. Such factors as a hot day, weak tow plane, strong wind, or other traffic may require a greater altitude to make a return to the airport a viable option. According to test result notations in the manufacturer's documentation of an internal technical flight conducted in 1999, the glider stalled at 35 knots in a landing straight flight stall, and stalled at 37 knots in a landing turn stall. According to instructions in the Aircraft Flight and Maintenance Manual (AFMM): Section 3.2. Spin Recovery; the height loss for a spin turn is approximately 262 to 295 feet with a speed at spin recovery of approximately 81 to 86 knots. According to FAA Advisory Circular AC No: 61-67C; Subject: Stall and Spin Awareness Training: Chapter 1: " … The possibility of inadvertently stalling the airplane by increasing the load factor (i.e., by putting the airplane in a steep turn or spiral) is much greater than in normal cruise flight … Excessively steep banks should be avoided because the airplane will stall at a much higher speed … If the nose falls during a steep turn, the pilot might attempt to raise it to the level flight attitude without shallowing the bank. This situation tightens the turn and can lead to a diving spiral. … If recovery from a stall is not made properly, a secondary stall or a spin may result. A secondary stall is caused by attempting to hasten the completion of a stall recovery before the aircraft has regained sufficient flying speed ... 14 Code of Federal Regulations 91.107 requires that each person must occupy an approved seat with a safety belt, except that a person may be held by and adult who is occupying an approved seat, provided that the person being held has not reached his or her second birthday and does not occupy or use any restraining device. Two other pilots reported that they had previously inadvertently made take-offs in the IS-28B2 glider with the tow dolly still attached. Both of them reported that there was no change in the flight characteristics in that condition except for a "whistling noise". One of the pilots said the glider actually handled better with the tow dolly attached. According to a postaccident sample weight and balance calculation by the operator; the center of gravity (CG) with all three passengers and without the tow dolly was 27.59 percent MAC. Adding the weight of the tow dolly shifted the CG to 30.96 percent MAC. The allowable range was from 22 to 47 percent MAC. MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy was performed on the pilot by the Galveston County Medical Examiner's Office, Texas City, Texas. Forensic toxicology was performed on specimens from the pilot by the FAA, Aeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The toxicology report was negative for ethanol and was negative for drugs. The Chief Medical Officer for the National Transportation Safety Board reviewed the pilot's FAA blue ribbon medical file, the FAA medical review, the autopsy findings, the toxicology results, the NTSB database for information regarding a previous glider accident, and the investigator's report. According to the FAA blue ribbon medical file, the pilot initially received a third class medical certification in 1965. He reapplied and was granted a third class medical certificate in 1983 and biannually thereafter. When the pilot applied for medical certification in 1989, he reported 81 total hours of flight time and a new diagnosis of diabetes. He also reported having a glider accident in August, 1989 in which he suffered a T12 compression fracture. A review of the NTSB accident database regarding that accident revealed that the pilot's glider experienced an inflight breakup due to severe turbulence and the pilot parachuted to safety from 6,500 feet. As a result of his diagnosis of diabetes, in 1990 the pilot was awarded a special issuance third class medical certificate, limited to one year. The pilot did not apply for

Probable Cause and Findings

The pilot’s failure to maintain adequate airspeed during an emergency situation, which resulted in an aerodynamic stall and subsequent impact with terrain. Contributing to the accident was the pilot’s acute coronary event, which resulted from his severe coronary artery disease, prior physical exertion, and the stress of the emergency situation.

 

Source: NTSB Aviation Accident Database

Get all the details on your iPhone or iPad with:

Aviation Accidents App

In-Depth Access to Aviation Accident Reports