N524SCPiper PA-28-181 · 2019

On December 21, 2009, at 1304 eastern standard time, a Czech Aircraft Works Sportcruiser special light sport airplane, N524SC, operated by Tidewater Flight Center, was substantially damaged during collision with trees and terrain following an inadvertent spin and dive recovery near Suffolk, Virginia. The certificated private pilot sustained minor injuries, and the certificated flight instructor was seriously injured. Visual meteorological conditions prevailed for the local instructional flight that originated at Chesapeake Regional Airport (CPK), at 1245, and was conducted under the provisions of 14 Code of Federal Regulations Part 91.

In both a telephone interview and a written statement, the pilot stated that he was recently issued his private pilot certificate and that the purpose of the flight was to be “checked out” in the Sportcruiser airplane. After departure, he flew the airplane a short distance to the training area to perform basic flight maneuvers. While flying about 2,500 feet mean seal level (msl); the pilot initiated a power-off stall. At the onset of the stall, he added power, the airplane “yawed left,” he applied right rudder and the airplane “snapped into a tight spin to the left.”

According to the instructor, the pilot was performing slow-flight maneuvers, and because the airplane was already configured, she suggested he perform a power-off stall. She said, "He reduced power to idle, and as the airspeed decreased, he increased the pitch attitude to induce a stall. We were climbing through to about 2500 feet MSL at this point. The aircraft then started veering to the left. He attempted to correct, but before he could do so with enough rudder the Sport Cruiser rolled into a spin."

The instructor announced that she had the flight controls, and the pilot released the controls. The instructor verbalized her spin recovery control inputs as she performed them, but the airplane continued to spin and lose altitude. The airplane eventually stopped spinning, and during the post-spin dive recovery, the airplane struck trees and terrain, and came to rest inverted.

The flight instructor was interviewed by telephone and her statement was consistent with the pilot’s. Both she and the pilot stated that it was a “surprise” how quickly the airplane rolled into the spin after the stall. Each of them also described the handling characteristics of the airplane as “touchy” and “sensitive” to control inputs, but during slow flight the controls were “mushy.”

A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a private pilot certificate with a rating for airplane single-engine land. His most recent FAA second class medical certificate was issued February 26, 2008. The pilot reported 99 total hours of flight experience with no prior experience in the accident airplane make and model.

A review of FAA airman records revealed that the flight instructor held a commercial pilot certificate with a rating for airplane single-engine land and instrument airplane. She also held a flight instructor certificate with a rating for airplane single-engine land and instrument airplane. Her most recent FAA second class medical certificate was issued July 11, 2008. The flight instructor reported 470 total hours of flight experience with 20 total hours of experience in the accident airplane make and model.

According to FAA and maintenance records, the airplane was manufactured in 2007 and had accrued 868 total aircraft hours. Its most recent conditional inspection was completed on November 17, 2009, at 826 total aircraft hours.

As of April 4, 2009, Czech Sport Aircraft owned the design rights for the SportCruiser and provided airworthiness support for all of the SportCruisers that were built by Czech Aircraft Works and subsequently by Czech Sport Aircraft.

On January 19, 2010, the SportCruiser was renamed the PiperSport and was distributed worldwide by PiperSport Distribution Inc.

On January 13, 2011, Piper Aircraft Inc. terminated its licensing agreement and the Sportcruiser was then distributed worldwide by Czech Sport Aircraft.

At 1944, the weather reported at TLH included clear skies and calm wind. The visibility was 10 miles. The temperature was 15 degrees C and the dew point was 12 degrees C. The altimeter setting was 30.23 inches of mercury.

At 1300, the weather reported at CPK, 10 miles east of the site, included scattered clouds at 4,900 feet and wind from 280 degrees at 6 knots. The visibility was 10 miles. The temperature was 7 degrees C and the dew point was -4 degrees C. The altimeter setting was 30.09 inches of mercury.

Examination of the airplane at the scene by an FAA inspector revealed substantial damage to the engine compartment, and partial separation of the wings. The airplane was recovered from the site on December 29, 2009, and examination during recovery revealed no pre-impact mechanical anomalies.

The accident airplane was involved in a previous accident on December 23, 2008 (NTSB ID ERA09LA111). The investigation compared the actual, published, and placarded (on the airspeed indicator) v-speeds for the airplane, and none matched. Further, the investigation determined that the calibrated-to-indicated airspeed chart published in the Pilot Operating Handbook (POH) was inaccurate.

As a result of the investigation, the pitot-static system on the SportCruiser was modified by inclusion of an AVIATIK WA037383 pitot-static probe in place of the previous design. The airspeed data was recomputed following flight tests that established calibrated airspeed (CAS), and compared it to the indicated airspeed (IAS) in the airplane. The POH was republished with the airspeed data derived from the flight tests and added a caution that "Airspeeds values are valid for standard AVIATIK WA037383 pitot-static probe."

The airplane experienced its second accident and was returned to service prior to the publication of the factual report for ERA09LA111, and the subsequent changes to the POH. Therefore, at the time of the second accident, the following information excerpted from ERA09LA111 still applied to the accident airplane:

The installed airspeed indicator's markings (miles per hour on the outside arc and knots on the inside arc) and airspeed color code range markings were different, from the airspeed indicator markings (knots only) and airspeed color code range markings shown on the airplane manufacturer's website for their "Standard 6-PAK" installation.

Further examination of the photographs also revealed that the installed airspeed indicator color code markings did not agree with the information published in the supplied airplane manufacturer's POH (Revision 1.0) which was published in March of 2006. Moreover, it was also discovered that not only did the color code range markings on the accident airplane not agree with the manufacturer's POH but also that the markings were inaccurate.

For example:

1. The bottom of the white arc (stall speed with flaps extended) was approximately 5 knots higher than published.

2. The top of the white arc (maximum flaps extended speed) was 10 knots lower than published.

3. The bottom of the green arc (stalling speed with flaps retracted) was approximately 3 knots higher than published.

ASTM Standards and the POH

Review of ASTM International's Standard Specification for Design and Performance of a Light Sport Airplane (ASTM Designation: F 2245-07), also revealed that "All flight speeds" were to be "presented" as "calibrated airspeeds."

Review of the supplied POH revealed however, that this was not the case, and that the airspeed limitations, and airspeed indicator markings published in the supplied POH, were actually presented as indicated airspeeds.

Furthermore, it was discovered that the stall speed information and airspeed indicator calibration information published in the POH in many cases contained large differences (in a couple of instances almost 20 knots) between the published indicated airspeeds and the published calibrated airspeeds.

Previous Special Light Sport Aircraft (SLSA) Airspeed Problems

This was not the first time that Safety Board investigators found Airspeed inconsistencies in SLSA airplanes and documents. Airspeed indicator, airspeed correlation, and POH inconsistencies were also discovered during investigations of a series of in-flight structural breakups of Zodiac CH-601XL airplanes that occurred in the United States between February of 2006 and March of 2009. During those investigations the Safety Board concluded that errors in airspeed correlation data would result in incorrect airspeed data in the pilot operating handbook (POH) and could result in a pilot inadvertently flying at unsafe airspeeds.

As a result of the investigation into the in-flight structural breakups, on April 14, 2009, the Safety Board issued recommendations to the FAA to:

"Determine the correct airspeed correlation between calibrated airspeed and indicated airspeed for the Zodiac CH-601XL, require that the correct data be included in existing and new airplane pilot operating handbooks (POHs), and ensure that the information on the airspeed indicator is accurate and consistent with the POHs. (Safety Recommendation A-09-36)."

"Work with ASTM International to incorporate additional requirements into the standards for light sport airplanes that provide for the accurate determination of airspeed data and for the adequate presentation of that data in existing and new airplane pilot operating handbooks and on airspeed indicators. (Safety Recommendation A-09-37)."

According to FAA Advisory Circular AC-61-23C, Pilot’s Handbook of Aeronautical Knowledge:

“The effect of torque increases in direct proportion to engine power, airspeed, and airplane attitude. If the power setting is high, the airspeed slow, and the angle of attack high, the effect of torque is greater. During takeoffs and climbs, when the effect of torque is most pronounced, the pilot must apply sufficient right rudder pressure to counteract the left-turning tendency...”

According to the FAA Airplane Flying Handbook, guidance for recovery from power-off stalls included, "Recovering from the stall should be accomplished by reducing the angle of attack, releasing back-elevator pressure, and advancing the throttle to maximum allowable power. Right rudder pressure is necessary to overcome the engine torque effects as power is advanced and the nose is being lowered. The nose should be lowered as necessary to regain flying speed and returned to straight-and-level flight attitude."

According to FAA Advisory Circular AC 61-67C, Stall and Spin Awareness Training:

107. SPINS. A spin in a small airplane or glider is a controlled (recoverable) or uncontrolled (possibly unrecoverable) maneuver in which the airplane or glider descends in a helical path while flying at an AOA greater than the critical AOA. Spins result from aggravated stalls in either a slip or a skid.

109. PRIMARY CAUSE. The primary cause of an inadvertent spin is exceeding the critical AOA while applying excessive or insufficient rudder and, to a lesser extent, aileron. Insufficient or excessive control inputs to correct for Power Factor (PF), or asymmetric propeller loading, could aggravate the precipitation of a spin. At a high AOA the downward moving blade, which is normally on the right side of the propeller arc, has a higher AOA and therefore higher thrust than the upward moving blade on the left. This results in a tendency for the airplane to yaw around the vertical axis to the left. If insufficient or excessive rudder correction is applied to counteract PF, uncoordinated flight may result. A classic situation where PF could play an important role in a stall/spin accident is during a go-around or short field takeoff where the airplane is at a high pitch attitude, high power setting, and low airspeed.

On December 23, 2008, about 1445 eastern standard time, a Czech Aircraft Works, SportCruiser, N1044Y, was substantially damaged during landing at Emporia-Greensville Regional Airport (EMV), Emporia, Virginia. The student pilot was not injured. Visual meteorological conditions prevailed for the flight, which departed Chesapeake Regional Airport (CPK), Norfolk, Virginia at approximately 1354. No flight plan was filed for the solo cross-country training flight conducted under Title 14 Code of Federal Regulations Part 91.

According to the student pilot, he was landing at EMV during his first cross country flight. While in the airport traffic pattern for landing on runway 15, he encountered a “strong wind gust.” during the downwind to base turn. After turning final he was "well above the approach path indicator." He then “encountered difficulty” in “getting the plane on the runway.” During the “flare” the airplane floated. He applied a “small amount of power,” to keep the airplane from stalling, and as the airplane continued to fly above the runway it began to drift to the left. After the airplane “touched down,” the student heard and felt the left main landing gear impact something.

The accident airplane was a two seat, single - engine, low wing monoplane, equipped with tricycle type landing gear and powered by a 98.6 horsepower, Rotax 912 ULS. It was registered in the Special Light Sport Aircraft (SLSA) category and was supposed to conform to ASTM standard specifications for design and performance of light sport airplanes.

According to FAA and maintenance records, the airplane was manufactured in 2007. The airplane’s most recent conditional inspection was completed on December 5, 2008. At the time of the accident, the airplane had accumulated 658 total hours of operation.

According to pilot records, the student pilot did not possess a FAA medical certificate. He reported 21 total hours of flight experience.

A weather observation taken at EMV, about 5 minutes prior to the accident, included; variable winds from 120 degrees to 200 degrees at 7 knots, 10 statute miles visibility, sky clear, temperature 3 degrees C, dew point -11 degree C, and an altimeter setting of 30.63 inches of mercury.

According to the Airport Facility Directory, EMV had one runway oriented in a 15/33 configuration. Runway 15 was 5044 feet long and 100 feet wide. Its surface was asphalt in fair condition. The runway markings were non-precision in poor condition and the runway edge markings were badly faded. A 2-light precision approach path indicator was installed on the left side of the runway that provided a 3-degree glide path.

Examination of runway 15 by a Federal Aviation Administration (FAA) inspector revealed, that a runway light on the left side of the runway had been broken off at its base. The housing displayed impact damage and its lens was broken.

Examination of the airplane revealed no preimpact malfunctions of the airplane or engine. The fuselage skin was wrinkled on the left side of the airframe above the wing fuselage juncture and a vertical line of rivets had pulled through the fuselage skin. The main support structure, which the left main landing gear was mounted to, was bent and the surrounding fuselage skin was wrinkled. The left main landing gear had been displaced aft by approximately 3 inches. The nose landing gear assembly had also been displaced and twisted to the left, and the center console and the interior flooring were bent and buckled.

The pitch control system was also found to be inoperative. Further examination revealed that the fuselage structure had come into contact with a bell crank, and a rod end from a push pull tube that attached to the bell crank was broken.

On January 2, 2009 during a series of post accident interviews, the student pilot's flight instructor advised the NTSB that his student had a "tendency" to be "high on final." He would teach his students to use the precision approach path indicator "as a reference, but not to chase it," and to "be on it or above it." He would rather that they "be high for safety." He would also, "really stress go-arounds."

The student pilot also advised the NTSB that he should have "gone around" but he was a "little confused about the airspeed at the time."

Precision Approach Path Indicator (PAPI)

According to the FAA's Technical Operations Navigation Services Group, The PAPI normally consists of four equi-spaced light units which are color coded to provide a visual indication of an aircraft's position relative to the designated glideslope for the runway. An abbreviated system consisting of two light units can be used for some categories of aircraft operations. PAPI provides guidance down to flare initiation (typically 50 ft).

The PAPI is usually located on the left hand side of the runway at right angles to the runway centre line. In good visibility conditions the guidance information can be used at ranges up to five miles by day and night. At night the light bars can be seen at ranges of at least twenty miles.

Each light unit consists of one or more light sources, red filters and lenses. Each light unit emits a high intensity beam. The lower segment of the beam is red and the upper part white. Depending on the position of the airplane relative to the specified angle of approach, the lights will appear either red or white to the pilot The pilot will have reached the normal glidepath (usually 3 degrees) when there is an even number of red and white lights. If an aircraft is beneath the glidepath, red lights will outnumber white; if an aircraft is above the glidepath, more white lights are visible.

Approach and Landing Guidance

According to the FAA's Airplane Flying Handbook (FAA-H-8083-3A), the objective of a good final approach is to descend at an angle and airspeed that will permit the airplane to reach the desired touchdown point at an airspeed which will result in minimum floating just before touchdown; in essence, a semi-stalled condition. To accomplish this, "it is essential that both the descent angle (glide path) and the airspeed be accurately controlled." Since on a normal approach the power setting is not fixed as in a power-off approach, the power and pitch attitude should be adjusted simultaneously as necessary, to control the airspeed, and the descent angle, or to attain the desired altitudes along the approach path.

The FAA stated that the roundout and touchdown should be made with the engine idling, and the airplane at "minimum controllable airspeed," so that the airplane will touch down on the main gear at approximately stalling speed. As the airplane settles, the proper landing attitude is attained by application of whatever back-elevator pressure is necessary. Some pilots may try to force or fly the airplane onto the ground without establishing the proper landing attitude. The airplane should never be flown on the runway with excessive speed. It is paradoxical that the way to make an ideal landing is to try to hold the airplane’s wheels a few inches off the ground as long as possible with the elevators. In most cases, when the wheels are within 2 or 3 feet off the ground, the airplane will still be settling too fast for a gentle touchdown; therefore, this descent must be retarded by further back-elevator pressure. Since the airplane is already close to its stalling speed and is settling, this added back-elevator pressure will only slow up the settling instead of stopping it. At the same time, it will result in the airplane touching the ground in the proper landing attitude, and the main wheels touching down first so that little or no weight is on the nosewheel.

Furthermore, The FAA also stated that, whenever landing conditions are not satisfactory, a go-around is warranted. There are many factors that can contribute to unsatisfactory landing conditions. Situations such as air traffic control requirements, unexpected appearance of hazards on the runway, overtaking another airplane, wind shear, wake turbulence, mechanical failure and/or an unstabilized approach are all examples of reasons to discontinue a landing approach and make another approach under more favorable conditions. The assumption that an aborted landing is invariably the consequence of a poor approach, which in turn is due to insufficient experience or skill, is a fallacy. The go-around is not strictly an emergency procedure. It is a normal maneuver that may at times be used in an emergency situation. Like any other normal maneuver, the go-around must be practiced and perfected. The flight instructor should emphasize early on, and the student pilot should be made to understand, that the go-around maneuver is an alternative to any approach and/or landing.

Airspeed Indicator and Pilots Operating Handbook (POH)

According to the FAA, indicated airspeed (IAS) is the airspeed that is read directly from the airspeed indicator on an aircraft, driven by the pitot-static system. It is an important value for the pilot because it directly indicates stall speed and various airframe structurally limited speeds, regardless of density altitude. IAS is also directly related to calibrated airspeed (CAS), which is the IAS corrected for instrument and installation errors.

As a result of the students statement that he was a "little confused about the airspeed at the time" NTSB investigators examined photographic evidence of the airplane's cockpit that was provided by the FAA and the airplane manufacturer, and the airspeed information that was published in the airplane manufacturer's POH.

Examination of the photographs revealed, that the installed airspeed indicator's markings (miles per hour on the outside arc and knots on the inside arc), and airspeed color code range markings were different, from the airspeed indicator markings (knots only) and airspeed color code range markings shown on the airplane manufacturer's website for their "Standard 6-PAK" installation.

Further examination of the photographs also revealed that the installed airspeed indicator color code markings did not agree with the information published in the supplied airplane manufacturer's POH (Revision 1.0) which was published in March of 2006. Moreover, it was also discovered that not only did the color code range markings on the accident airplane not agree with the manufacturer's POH but also that the markings were inaccurate.

For example:

1. The bottom of the white arc (stall speed with flaps extended) was approximately 5 knots higher than published.

2. The top of the white arc (maximum flaps extended speed) was 10 knots lower than published.

3. The bottom of the green arc (stalling speed with flaps retracted) was approximately 3 knots higher than published.

ASTM Standards and the POH

Review of ASTM International's Standard Specification for Design and Performance of a Light Sport Airplane (ASTM Designation: F 2245-07), also revealed that "All flight speeds" were to be "presented" as "calibrated airspeeds."

Review of the supplied POH revealed however, that this was not the case, and that the airspeed limitations, and airspeed indicator markings published in the supplied POH, were actually presented as indicated airspeeds.

Furthermore, it was discovered that the stall speed information and airspeed indicator calibration information published in the POH in many cases contained large differences (in a couple of instances almost 20 knots) between the published indicated airspeeds and the published calibrated airspeeds.

Previous SLSA Airspeed Problems

This was not the first time that Safety Board investigators had found Airspeed inconsistencies in SLSA airplanes and documents. Airspeed indicator, airspeed correlation, and POH inconsistencies were also discovered during investigations of a series of in-flight structural breakups of Zodiac CH-601XL airplanes that occurred in the United States between February of 2006 and March of 2009. During those investigations the Safety Board concluded that errors in airspeed correlation data would result in incorrect airspeed data in the pilot operating handbook (POH) and could result in a pilot inadvertently flying at unsafe airspeeds.

As a result of the investigation into the in-flight structural breakups, on April 14, 2009, the Safety Board issued recommendations to the FAA to:

"Determine the correct airspeed correlation between calibrated airspeed and indicated airspeed for the Zodiac CH-601XL, require that the correct data be included in existing and new airplane pilot operating handbooks (POHs), and ensure that the information on the airspeed indicator is accurate and consistent with the POHs. (Safety Recommendation A-09-36)."

"Work with ASTM International to incorporate additional requirements into the standards for light sport airplanes that provide for the accurate determination of airspeed data and for the adequate presentation of that data in existing and new airplane pilot operating handbooks and on airspeed indicators. (Safety Recommendation A-09-37)."

In order to correct the problems with the SportCruiser's airspeed indicators, and POH inconsistencies, Czech Aircraft Works took the following actions:

1. The pitot-static system on the SportCruiser was modified by inclusion of an AVIATIK WA037383 pitot-static probe in place of the previous design.

2. The airspeed data was recomputed using data from flight testing to establish CAS, which was then compared directly to the IAS in the airplane.

3. The POH was republished with the airspeed data derived from the flight tests and added a caution that "Airspeeds values are valid for standard AVIATIK WA037383 pitot-static probe."

Czech Sport Aircraft

On April 4, 2009, Czech Sport Aircraft advised that it was now the owner of the design rights for the SportCruiser and would be providing continuing airworthiness support for all of the SportCruisers that were built by Czech Aircraft Works and subsequently by Czech Sport Aircraft.

On January 19, 2010, Czech Sport Aircraft advised the SportCruiser was renamed the PiperSport and would now be distributed worldwide by PiperSport Distribution Inc.