Aviation Accident Summaries

Aviation Accident Summary LAX08GA239

Salt Lake CIty, UT, USA

Aircraft #1

N11

BEECH A200

Analysis

The instructor pilot stated that after takeoff and while conducting flight maneuvers, he noticed an unsafe gear indication. The three green lights were extinguished; however, the red "gear transit" light was illuminated. The landing gear visually appeared to be down. The instructor pilot recycled the landing gear, which continued to fail to lock in the extended position. The pilot returned to the airport and executed a low approach over the runway where tower personnel advised them that the landing gear appeared to be down. The crew decided to attempt a landing with the unsafe landing gear indication. After touchdown, the main landing gear partially collapsed, while the nose gear remained extended. A previous incident similar to the accident occurred 14 weeks before. During that event, the flight crew manually extended the gear per the prescribed procedures and made a successful landing. During the accident event, the flight crew did not attempt to manually lower the landing gear as directed in the (checklist). Post accident inspection of the landing gear motor and relay system found that there were worn and chipped sprocket teeth, one of the sprocket shafts was not square with the gear, and at least one of the hanger bearings was worn.

Factual Information

On July 21, 2008, about 1430 mountain daylight time (MDT), a Beech A200, N11, experienced a partial landing gear malfunction resulting in a gear-up landing at Salt Lake City International Airport (SLC), Salt Lake City, Utah. The Federal Aviation Administration (FAA) was operating the public-use airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The two airline transport pilots were uninjured, and the airplane sustained substantial damage to the lower fuselage. The local FAA 4040 currency flight departed SLC about 1412. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot-in-command reported that during an FAA currency flight, they took off from SLC. After obtaining a positive rate of climb, he selected the gear-up handle. The pilot observed that the three green lights extinguished and the red “gear transit” light illuminated; however, the landing gear had not retracted. He attempted to recycle the gear, which failed to lock in the down position. The pilot returned to the airport and made a low approach over the runway. During the flyby, tower personnel advised the pilot that the gear appeared to be down. The pilots then decided to attempt a landing to runway 35. About 45 knots and after touchdown, the main landing gear partially retracted. The nose gear remained extended. The airplane slid down the runway. During the examination of the airplane, it was discovered that the 60-amp thermal circuit breaker for the landing gear motor had tripped. The landing gear motor and landing gear transmission were recovered for further examination. PERSONNEL INFORMATION CHECK PILOT- Pilot-in-Command A review of FAA airman records revealed that the 47-year-old FAA Aviation Safety Inspector/Instructor pilot held a second-class aviation medical certificate and an airline transport pilot certificate with ratings for airplane multi-engine land and instrument airplane, as well as a Certified Flight Instructor (CFI) license for airplane single-engine and multi-engine. The instructor pilot reported that he had a total flight time of 3,750 hours. About 73 hours were logged in the last 90 days, and 10 hours in the last 30 days. An estimated 64 hours had been flown in this make and model airplane involved in the accident. The pilot completed a biennial flight review on June 5, 2008. SECOND PILOT The second pilot was an FAA Aviation Safety Inspector who held a second-class aviation medical certificate, and an airline transport pilot certificate with ratings for airplane multi-engine land and instrument airplane, as well as a CFI license for airplane single-engine and multi-engine. The second pilot reported that he had a total flight time of 4,900 hours. About 10 hours had been logged in the last 90 days, and 10 hours in the last 30 days. An estimated 64 hours had been flown in the make and model airplane involved in the accident. The pilot completed a biennial flight review on June 5, 2008. AIRCRAFT INFORMATION The airplane was a Beech A200, serial number BD-001. A review of the airplane’s logbooks revealed that the airplane had a total airframe time of 7,418 hours, and 9,518 landings at the time of the accident flight. Examination of the maintenance and flight department records revealed no unresolved maintenance discrepancies against the airplane prior to departure. METEOROLOGICAL INFORMATION The closest official weather observation station was Salt Lake City (SLC). The elevation of the weather observation station was 4,227 feet mean sea level (msl). An aviation routine weather report (METAR) at SLC was issued at 1453. It indicated: Winds from 030 degrees at 8 knots; visibility 10 miles; skies 15,000 feet broken; temperature 28 degrees Celsius/; dew point 11 degrees Celsius; and altimeter 30.06 inches of mercury. COCKPIT VOICE RECORDER The airplane was equipped with a Cockpit Voice Recorder (CVR) and a Digital Flight Data Recorder (DFDR). Both recorders were removed from the airplane shortly after the accident, and were later sent to the National Transportation Safety Board Vehicle Recorder Division in Washington, DC, for readout. The recorders were in excellent condition and provided good information. A CVR Group was formed at NTSB Headquarters on September 16, 2008. The group reviewed the tape recording and developed a CVR transcript. The CVR recording began at 13:59:14. The recording contained events from just prior to takeoff, continued uninterrupted thru the entire flight, and ended when the airplane was shut down on the runway. The recording ended at 14:31:12. The following significant events were taken from the CVR transcript. At 14:10:43, SLC Tower cleared N11 for takeoff using runway 35. At 14:12:06, The PIC (non flying pilot) advised the second pilot (flying pilot (FP)), that the airspeed was 110 knots, rotate. At 14:12:11, PIC advised, “We got positive rate.” At 14:12:13, FP called for “gear up.” At 14:12:14, PIC advised, “Gear’s coming up.” At 14:12:15, sound similar to the landing gear motor]. For the next almost two minutes, the flight crew is heard conducting normal flight operations. At 14:14:10, PIC called for after take-off checklist, “Landing gear? Power set?” For the next minute and 10 seconds, the crew is heard talking about power settings, yaw damper, and altitude. At 14:15:20, PIC advised FP, “After take-off checklist.” At 14:15:38, FP advised, “Alright leaving five thousand five hundred for eight thousand five hundred. Confirm?” At 14:15:43, PIC stated, “Okay. Yup. And after take-off checklist is complete.” At 14:15:58, PIC stated, “Just don’t worry about the master caution. It’s the…we have a landing gear light.” At 14:16:34, PIC called for the FP to lower the landing gear. At 14:16:43, PIC advised that the landing gear was down and asked to bring it up again. At 14:17:27, FP asked if the gear was still down. At 14:17:29, PIC advised it still was down and told the FP to return to SLC so they can do a precautionary landing. At 14:19:23, PIC advised approach control that, “The landing gear appears to be down we just have an unsafe indication.” At 14:21:01, PIC advised the FP that they were going to do a low approach. He confirmed that the FP could see the right side main landing gear down. At 14:23:57, SLC Tower reports to the flight crew that, “They appear to be all down.” At 14:24:09, PIC advised SLC Tower that they were going to land on runway 35. At 14:24:14, SLC Tower asked if they wanted emergency equipment for the landing. At 14:24:18, PIC advised that it was not necessary. For the next four minutes, the flight crew is heard positioning the airplane for landing. At 14:28:16, the PIC took the controls as the flying pilot. At 14:28:36 the FP stated, “The gear still appears down.” At 14:28:58, [sound similar to landing gear warning horn]. At 14:29:01, EGPWS too low gear. [repeats 24 times]. At 14:29:19, the PIC stated, “It must be a faulty indication. We’ll see when we land though.” At 14:29:50, [sound similar to decrease in engine rpm]. At 14:30:00, [sound similar to touchdown and a sound of a thump]. At 14:30:05, [sound of scraping]. At 14:30:11, the PIC stated, “Something happened.” At 14:30:12, the FP stated, “The left side’s down” The PIC acknowledged the FP and called for the engine shutdown. At 14:30:33, [sound of scraping stops]. At 14:30:55, the PIC transmitted to the SLC tower that they needed assistance on the runway with no fire, just the landing gear collapsed. At 14:31:12, end of recording. WRECKAGE AND IMPACT INFORMATION Investigators examined the wreckage in a hangar at the Salt Lake City International Airport on July 23, 2008. The left inboard flap exhibited scraping damage on the trailing edge out to 3 feet 4 inches, and the right inboard flap exhibited scraping damage on the trailing edge out to 3 feet. According to a representative from Hawker Beechcraft, the lower fuselage, skin, frames, and stringers were damaged from extensive scraping between stations number 273.52 (fore) and station number 326.750 (aft). Several antennae and a light were damaged on the airplane’s belly. The Hawker Beechcraft representative stated that both the left and right landing gear actuator nuts were fractured because of bending loads from supporting the airplane’s weight. Both the left and right landing gear support brackets were damaged. The Hawker Beechcraft representative reported evidence of damage to the front wing spar web on the right wing where the landing gear and upper spar cap connect. No such evidence was found on the left wing. The crossover shafts from the landing gear motor to the main landing gear were free and rotated smoothly. TESTS AND RESEARCH The airplane was flown to the FAA maintenance facility located in Oklahoma City, Oklahoma, for repairs and further examination of the landing gear motor and the landing gear relay system. The accident airplane was inspected by FAA maintenance personnel for conditions that could cause the landing gear malfunction. The results were: * An estimated approximately 60 percent of the sprocket teeth were worn and chipped. These are not considered to be life limited components nor is there any inspection requirement, except for the cycling of the gear. * It was also found that one of the sprocket shafts was not completely squared with the gear. * At least one of the hanger bearings was worn on the edge where the chain was rubbing due to wear in sprockets, sprocket teeth, and misaligned gear to shaft. ADDITIONAL INFORMATION The operator of the airplane reported that on April 14, 2008, the accident airplane had a similar landing gear malfunction while being operated for the FAA Turboprop Recurrent Training at Dothan, Alabama. In that event the pilots performed the landing gear manual extension procedures and landed the airplane without further incident. The total flight time on the airplane was 7,321.3 hours, with 9,387 landings recorded. A review of the on-board checklist for the accident airplane revealed guidance for the manual extension of the landing gear in the event of a landing gear malfunction. The flight crew involved in the accident did not attempt a manual gear extension prior to the landing.

Probable Cause and Findings

The failure of the landing gear motor (worn components) resulting in the partial collapse of the landing gear during landing. Contributing to the accident was the flight crew not following emergency checklist procedures to attempt a manual gear extension.

 

Source: NTSB Aviation Accident Database

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