Monroe, GA, USA
N42BF
SOCATA MS894A
After takeoff from his home airport, the pilot flew his airplane to a nearby airport to practice landings. After arrival at the nearby airport, the pilot performed a touch and go landing but decided to return to his home airport because the wind was increasing. When the airplane was in level flight at 2,500 ft mean sea level and was about 16 nautical miles from the destination airport, the upper portion of the engine cowling departed the airplane, punctured the windscreen, and became lodged against the empennage; as a result, the pilot had difficulty controlling the airplane, which was no longer able to maintain level flight. The pilot elected to make a landing in a field, and the airplane struck a large tree and a swing on residential property. During the separation of the cowling and the subsequent forced landing, the airplane sustained substantial damage. Postaccident examination of the cowling latching mechanism revealed that all four lower catches were intact, but the left forward upper lever was worn and corroded and had broken, causing the upper engine cowling to depart the airplane. Further examination of the broken latch also revealed that the latching mechanism, which had been attached to the handle, was missing along with the shear pin, which kept the latching mechanism attached to the handle. The hook and shaft subassembly appeared to be missing in the broken latch. Also, the pinhole where the mechanism’s right side would have been attached, displayed damage around the pinhole, consistent with the smearing of material from an adjacent component sliding along the surfaces. The smearing direction was generally outward and parallel to the sliding and impact damage on the adjacent rivet head. In addition, material was deformed outward from the pinhole, including outward smearing on the hole edge. This deformation was parallel to and consistent with the other smearing features on the latch body interior. Witness marks and the absence of the hook and shaft subassembly were consistent with the loss of the pin. Thus, when the shear pin, which was not recovered, fractured, the pin remnant likely came out of one of the holes and then tore out of the other hole in a bending direction, damaging the adjacent housing rivet head. The pilot had performed, as part of his pre-flight inspection before the accident flight, a check of the cowling latches in accordance with a manufacturer service bulletin and a Federal Aviation Administration airworthiness directive (AD), both of which had been issued to prevent the possible loss of an engine cowling due to improper latching of locks and cowl lock wear. The pilot reported that the preflight inspection was “normal.” The AD required in part that, maintenance personnel visually inspect the engine lower cowling metal centering tabs and the upper cowling centering pins for wear of the metal tab receiving holes and wear of the centering pins to ensure proper mating of the upper and lower cowling. The metal centering tabs and cowling centering pins were to be replaced if found to be worn. The AD also required maintenance personnel to inspect the engine cowling locking mechanism and, if deterioration in locking push force is evident, adjust the engine cowl lock by removing the cotter pin in the upper catch, threading the latch trunnion into the upper catch a distance of one or more turns, and reinserting the cotter pin. These inspections were to occur within 25 hours after the AD was issued and then within 100 hours of time in service from the last inspection. Review of the airplane’s maintenance records found logbook entries from 1977 to 2015 that indicated that the recurring AD had been accomplished and that no adjustments were needed, and no defects were noted. However, the AD was not consistently performed according to the specified time requirement. Additionally, between the time of the last inspection and the accident, the airplane had been operated for about 204 hours, but maintenance records showed no other entries indicating compliance with the AD. The most recent document in the logbook, an AD compliance report for the airplane, showed that the AD was previously complied with, even though it was a recurring AD. Therefore, the upper engine cowling likely separated from the airplane due to maintenance personnel’s failure to perform the required inspection of the engine cowling latches.
On March 15, 2021, about 1514 eastern daylight time, a Socata MS894A airplane, N42BF, was substantially damaged when it was involved in an accident in Monroe, Georgia. The pilot sustained minor injuries. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. According to the pilot, about 1400 on the day of the accident, he obtained weather and notice of air mission information for a roundtrip flight from Gwinnett County Airport – Briscoe Field (LZU), Lawrenceville, Georgia, to Cy Nunnelly Memorial Airport (D73), Monroe, Georgia, to perform practice landings. The wind was reported to be from 110° at 10 knots gusting to 15 knots at LZU and from 070° at 10 knots gusting to 15 knots at D73. The pilot reported that he had performed a preflight insepction, which included checking the cowling latches, and that the results were “normal.” The pilot also reported that taxi, takeoff, and departure were normal and that he elected not to have flight following for the short local flight. The airplane departed LZU about 1450 and flew to D73 at 3,500 ft mean sea level (msl), and the pilot received the latest automated weather observing system report for D73, which indicated that the wind was from 080° at 10 knots gusting to 15 knots with occasional gusts to 20 knots. The pilot delayed his traffic pattern entry to allow a Cessna to enter the left downwind leg of the traffic pattern for runway 2, and then the accident airplane entered a standard left downwind from a 45° entry once the pilot had the Cessna in sight. The Cessna landed uneventfully, and the accident airplane turned onto the final approach leg once the Cessna cleared the runway. The pilot performed a normal crosswind touch-and-go landing but noticed that the wind was increasing and decided to return to LZU earlier than planned. The airplane climbed straight out to pattern altitude, turned westbound toward LZU, and leveled off at 2,500 ft msl. The pilot received the automatic terminal information service information report, which indicated unchanged conditions since the time of the airplane’s departure. When the airplane was 16 miles from LZU, the cowling “suddenly” departed the airplane and struck the right side of the windscreen, puncturing a large hole from just left of the center post to about 10 inches from the right canopy bow. The pilot “was blasted with wind,” the airplane’s nose dropped sharply, and the airplane started to yaw sharply left and right. The pilot stated that he struggled to regain control and was not certain that the airplane was flyable. The pilot was eventually able to regain control, but the airplane would not turn right as easily as it turned left, so the pilot started a left descending turn. He hoped to fly to D73 and land. The pilot determined the airplane responded better at lower speeds, but the airplane was not able to maintain level flight, even with full power; at that point, the pilot realized that he needed to select an off-field landing site. The pilot continued to turn the airplane left while in a continuous descent. The airplane was unable to level off or climb. The pilot could look only to the left because of the intensity of the wind blast from the hole on the right portion of the windscreen, which also caused his prescription eyeglasses and headset to blow off. The pilot selected a large field running east-west that looked “fairly unobstructed” and would give him “a short run-out area.” The pilot was maintaining around 60 knots, and the leading-edge slats deployed normally. The pilot elected to not use flaps because he was concerned about changing the airplane’s configuration given the damage that the airplane had already sustained. The airplane touched down hard on the main gear about one-third of the way down the field, bounced, and touched down again at a point where the terrain started sloping uphill. The pilot started braking, and the airplane slowed but continued rolling until it struck a large tree and a free-standing swing on an A frame on residential property, causing substantial damage to the horizontal stabilizer and right wing. The pilot reported that, according to the sheriff’s department, the cowling was located near the point where the airplane touched down. The pilot believed that “the cowling had been lodged on the empennage and only dislodged when [he] landed.” Wreckage and Impact Information Postaccident examination of the cowling latching mechanism revealed that all four lower catches were intact. Examination of the upper levers revealed that the left forward upper lever displayed wear and corrosion and appeared to be broken. Further examination of the left forward upper lever and the right forward upper lever (used as an exemplar) revealed that both consisted of an outer housing that could be actuated over the latch assembly, affixed by two separate rivets. On the intact latch, a hook (the upper catch) was affixed to the latch through a riveted U-shaped clasp (the spring) that was inserted into a T- shaped shaft (the trunnion) and held in place via a cotter pin. This shaft was joined to the latch body by a shear pin. The hook and shaft subassembly appeared to be missing in the broken latch. On the right forward upper lever (the exemplar lever), just outside of the hook and clasp, randomly oriented scratch marks were located on the inside face. These scratches were also on the inside surface of the latch body on the broken latch. The number of scratches, as well as their depth and location, were comparable on both latch interiors. Further examination of the broken latch revealed that the pin was missing from the pinhole on its right side, the riveted connection was still intact, and the damage around the pin hole was consistent with smearing of material from an adjacent component sliding along the surfaces. The smearing direction was generally outward and parallel to the sliding and impact damage on the adjacent rivet head. In addition, material was deformed outward from the pin hole, including outward smearing on the hole edge. This deformation was parallel to and consistent with the other smearing features on the latch body interior. The opposite interior sides of the broken latch also exhibited a riveted connection with the outer housing adjacent to the pinhole, but the amount of damage was confined to circular wear marks around the pin hole. These wear marks were about 0.03 inches in width and were located around the opposite sides of the pin. These marks were consistent with interaction of the latch body surface with the sidewall of the T-shaped shaft. No other indications of damage were found on the broken cowling latch. The witness marks and the absence of the hook and shaft subassembly were consistent with the loss of the pin. Additional Information The pilot advised that he performed the cowling latch check (during the preflight inspection before the accident flight) according to Socata Rallye Service Bulletin 107. The pilot also advised that the airplane complied with Federal Aviation Administration (FAA) Airworthiness Directive (AD) 76-11-02. Review of Socata Rallye Service Bulletin 107 and AD 76-11-02 indicated that they were issued to prevent the possible loss of an engine cowling on Socata airplanes due to improper latching of locks and cowl lock wear. Further, AD 76-11-02 required the following: For airplanes incorporating Socata-type engine cowl locks, within the next 25 hours time in service after the effective date of this AD, and thereafter at intervals not to exceed 100 hours time in service from the last inspection – (1) Visually inspect the engine lower cowling metal centering tabs and the upper cowling centering pins, for wear of the metal tab receiving holes and wear of the centering pins to assure proper mating of the upper and lower cowling. Replace the metal centering tabs and cowling centering pins, found to be worn; and (2) Inspect the engine cowling locking mechanism and if deterioration in locking push force is evident as demonstrated by a lack of snap action on the latch locking lever, adjust the Socata type engine cowl lock by removing the cotter pin in the upper catch, threading the latch trunnion into the upper catch a distance of one or more turns, and reinserting the cotter pin in accordance with the procedure described in paragraphs 1 .2 and 3.1 of Socata Service Bulletin No. 107 Gr. 71-06, dated November 1972, or an FAA approved equivalent. The accident airplane’s maintenance records showed the following: - On March 22, 1977, at an unknown time in service, AD-76-11-02 was first accomplished. The entry indicated that the cowl was inspected and “needed no adjustment.” - On June 2, 1981, at 371 hours in service, the “cowling latch” was inspected. The entry stated, “no adjustment needed.” - On October 1, 1989, at 464 hours in service, an entry stated, “76-11-02 No adjustment required.” - On August 21, 2006, at 580 hours in service (116 hours since the last entry), AD-76-11-02 was accomplished. - On September 1, 2011, at 799 hours in service (219 hours since the last entry), the inspection was accomplished “with no defects noted.” - On January 1, 2013, at 836 hours in service, the inspection was accomplished with “no defects noted.” - On May 22, 2014, at 873 hours in service, the inspection was accomplished with “no defects noted.” - On October 1, 2015, at 901 hours in service, the inspection was accomplished with “no defects noted.” No other entries regarding compliance with the AD were noted after the October 1, 2015, inspection. At the time of the accident, the airplane had accrued 1,105 hours of service (about 204 hours since the October 2015 inspection). Additionally, the maintenance records contained an AD compliance report for the airplane, dated January 5, 2021, which listed the AD as “PCW” (previously complied with), even though the AD was considered to be a recurring AD.
Maintenance personnel’s failure to properly inspect and maintain the airplane’s engine cowling latches, which resulted in the in-flight separation of the engine cowling and a subsequent forced landing.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
