N53178

HISTORY OF FLIGHTOn March 5, 2015, about 1422 Pacific standard time, a Ryan Aeronautical ST3KR, N53178, sustained substantial damage during a forced landing following a reported loss of engine power shortly after takeoff and during initial climb-out from the Santa Monica Municipal Airport (SMO), Santa Monica, California. The airplane was registered to MG Aviation, Inc., and operated by the pilot under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot, who was the sole occupant of the airplane, was seriously injured. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. The local flight originated from SMO about 1421.

During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge, the pilot reported that, shortly after takeoff and about 1,100 ft mean sea level, the engine experienced a loss of power. He stated that he did not attempt an engine restart but maintained an airspeed of 85 mph and initiated a left turn back toward the airport; however, during the approach, he realized that the airplane was unable to reach the runway. The pilot did not recall anything further about the accident sequence. Subsequently, the airplane struck the top of a tree that was about 65 ft tall, and then impacted the ground in an open area of a golf course.

Examination of the accident site by an NTSB investigator revealed that the airplane came to rest upright adjacent to the 8th tee, about 800 ft. southwest of the approach end of runway 03 at SMO. The airplane sustained substantial damage to the wings, the right stabilizer, and the fuselage.

Multiple witnesses who were on the golf course reported hearing and observing the airplane overhead. Shortly thereafter, the witnesses heard the airplane's engine quit. The airplane was seen gliding toward the ground. Several witnesses observed the airplane strike the top of a tree and then descend to the ground.

The airplane was recovered to a secure location for further examination. PERSONNEL INFORMATIONThe pilot, age 72, held a private pilot certificate with airplane multi-engine land, single-engine land, airplane single-engine sea, rotorcraft-helicopter, and instrument ratings. The pilot was issued a third-class airman medical certificate on May 23, 2014, with the limitation that he must wear corrective lenses. The pilot reported on his most recent medical certificate application that he had accumulated 5,200 total flight hours. The pilot reported that he had accumulated a total of 55.3 hours within the preceding 90 days, 17.7 hours within the preceding 30 days, and logged no flight hours within the previous 24 hours. The total time he had logged in the accident make/model airplane was over 75 hours. AIRCRAFT INFORMATIONThe two-seat, low-wing monoplane, fixed-gear airplane, serial number (S/N) 1859, was manufactured in 1942. The military version of the airplane was known as the PT-22 Recruit. It was powered by a Kinner R-55 engine, serial number 07450, rated at 160 horsepower. The airplane was also equipped with a Sensenich model W90HASP-86, serial number AF 1893, fixed pitch propeller. The airplane is flown solo from the rear seat.

The accident make/model airplane was not equipped with shoulder harnesses when it was produced in 1942. However, the accident airplane was equipped with shoulder harnesses for both the forward and aft seats. No logbook entries, supplemental type certificate (STC), or documentation was located during the investigation that provided details on when the shoulder harnesses were installed in the airplane.

While it is typical to add shoulder harnesses in antique airplanes, most are performed under an STC installation or by a field approval from the Federal Aviation Administration (FAA). However, FAA guidance does allow for certain installations to be conducted under minor alterations as long as no welding or drilling of holes into the aircraft structure is performed. No evidence of drilling or welding was noted to the aircraft structure.

Review of the airframe and engine logbooks revealed that the most recent annual inspection was completed on March 13, 2014, at a recorded tachometer reading of 25 hours and an airframe total time of 163.5 hours since the restoration of the airplane. METEOROLOGICAL INFORMATIONA review of recorded data from the SMO automated weather observation station, located near the accident site, revealed that, at 1351, conditions were wind from 220 degrees at 10 knots, visibility 10 statute miles, clear sky, temperature 23 degrees Celsius, dew point -8 degrees Celsius, and an altimeter setting of 30.20 inches of mercury. AIRPORT INFORMATIONThe two-seat, low-wing monoplane, fixed-gear airplane, serial number (S/N) 1859, was manufactured in 1942. The military version of the airplane was known as the PT-22 Recruit. It was powered by a Kinner R-55 engine, serial number 07450, rated at 160 horsepower. The airplane was also equipped with a Sensenich model W90HASP-86, serial number AF 1893, fixed pitch propeller. The airplane is flown solo from the rear seat.

The accident make/model airplane was not equipped with shoulder harnesses when it was produced in 1942. However, the accident airplane was equipped with shoulder harnesses for both the forward and aft seats. No logbook entries, supplemental type certificate (STC), or documentation was located during the investigation that provided details on when the shoulder harnesses were installed in the airplane.

While it is typical to add shoulder harnesses in antique airplanes, most are performed under an STC installation or by a field approval from the Federal Aviation Administration (FAA). However, FAA guidance does allow for certain installations to be conducted under minor alterations as long as no welding or drilling of holes into the aircraft structure is performed. No evidence of drilling or welding was noted to the aircraft structure.

Review of the airframe and engine logbooks revealed that the most recent annual inspection was completed on March 13, 2014, at a recorded tachometer reading of 25 hours and an airframe total time of 163.5 hours since the restoration of the airplane. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane impacted terrain about 800 ft southwest of runway 03 at an elevation of about 45 ft. Wreckage debris remained within about 10 ft of the main wreckage. The first identified point of contact was the top of a tree about 65 ft tall. The first area of ground impact consisted of an area of disturbed grass that extended to a small crater of disturbed dirt, which contained a portion of the propeller blade. The ground scars were about 25 ft in length.

The fuselage came to rest upright on a heading of about 44 degrees magnetic about 150 feet from the tree. The wings and engine remained partially attached to the main fuselage. Flight control continuity was established to all flight surfaces, with the exception of the right aileron; its control cable became separated when the right wing partially detached from the wing root. All major structural components of the airplane were located at the accident site.

Fuel was observed leaking from the front of the airplane, and the responding fire department reported shutting off the airplane's fuel supply from the cockpit. ADDITIONAL INFORMATIONReview of Advisory Circular (AC) 21-34, dated June 4, 1993, provides basic principles regarding design and installation of combined shoulder harness and safety belt restraint systems. Section 4, Installation Geometry, item D, of AC 21-34 states in part "spinal compression is likely to occur when the upper end of the shoulder belt is mounted an excessive amount below the occupant's shoulder level…the shoulder belt pulls down and back on the torso as it resists the forward motion of the occupant. The resultant restraint force…will place the spinal column in compression, and will add to the stresses in the column caused by the vertical component of the impact deceleration force.

AC 21-34, Section 7, Structural Attachments provides three design concepts that are intended to create an understanding of the features needed in the attachments.

"Concept 1: The first concept is to spread attachment loads into as much surrounding structure as possible and as gradually as possible. Gradual dissipation of loads minimizes stress concentrations at abrupt changes in material cross section which promote local failures, either immediately or upon a subsequent accident load cycle.

Concept 2: The second concept is to minimize local structural bending by attachment loads. Semimonocoque structure generally offers poor resistance to bending, but is good in tension and shear applications. Airframe bending, buckling, or collapse adds to forward movement of the occupant.

Concept 3: The third concept is to ensure that fastener type, strength, and number are adequate in tension, shear, and bending, depending on the application. Airframe buckling under restraint loads will result in compound loading of connector plates as well as fasteners. Concurrently, material thickness is important in preventing fastener pull-out, and continued security (safety wire or equivalent) of threaded fasteners should be considered."

Item C of Section 7 states in part, "…some existing aircraft will already have shoulder harness attachment points, often called "hard points," which were installed during production. As an alternative, it is fortunate to be able to attach shoulder belts to reasonably rigid structure where only a doubler may be needed to replace the material removed for fastener holes. Most often, it is necessary to attach shoulder belts to relatively thin formed sections, or even skin panels, of semimonocoque construction to achieve a satisfactory geometric configuration of the belts when in use. In most cases, attachment points need reinforcement. Attachments to welded tube a...