N174RCessna P210N · 1978

On July 16, 2021, about 1529 central daylight time, a Cessna P210N, N174R, was substantially damaged when it was involved in an accident near Refugio, Texas. The pilot was not injured and his passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 business flight.

The pilot reported that he departed Mustang Beach Airport (RAS), Port Aransas, Texas, on runway 12 because the winds were about 10 knots from the southeast. After takeoff, he contacted air traffic control (ATC) to obtain his instrument flight rules clearance to Addison Airport (ADS), Addison, Texas. A plot of the airplane’s ground track during the flight is depicted in figure 1.

While climbing through 2,000 ft mean sea level (msl), the pilot and his passenger began to smell an odor in the cabin and eventually saw smoke emanate from the center control console. The pilot stated that at that time he did not know the source of the smoke. He subsequently declared an emergency with the air traffic controller and asked to land at the nearest airport.

According to ATC documentation, about 1517, the pilot told the air traffic controller that the airplane had a mechanical failure and that he needed to land at the nearest airport. The controller told the pilot the location of Rooke Field Airport (RFG), Refugio, Texas, and cleared him to descend. According to ADS-B track data, at 1518, the airplane entered a descent from 6,500 ft msl.

Figure 1 – Airplane ground track for flight

About 1519, the pilot told the air traffic controller that he had RFG in sight, and he was subsequently cleared for a visual approach to the airport. The airplane flew westbound past RFG about 4 miles before it made a right turn back toward the airport, as depicted in figure 1. The airplane then entered a short left downwind leg before turning onto final approach for runway 32R at RFG, as shown in figure 2.

Figure 2 – Airplane ground track during landing

According to the pilot, he was unable to extend the landing gear using the landing gear hydraulic power pack. He concluded that the source of the odor and smoke was likely from a hydraulic power pack motor failure, and he proceeded to extend the landing gear using the emergency landing gear extension procedure. However, after numerous pumps, the green landing gear down and locked position indicator did not illuminate on the instrument panel. The pilot reported that both main landing gear were extended and, as such, he concluded that the nose landing gear was likely not fully extended. He decided to continue with the approach to the runway with the flaps partially extended.

At 1528:41, the last ADS-B return was recorded over the displaced threshold for runway 32R at 150 ft msl (96 ft above the threshold elevation). At that time, the airplane’s calibrated airspeed and ground speed were 83 knots, 99 knots, respectively, as depicted in figure 3. The airplane’s vertical speed and flight path angle were -1,013 ft per minute and -6.8°, as depicted in figure 3 and figure 4, respectively. The airplane’s ground track and descent profile were consistent with a landing on runway 32R.

The pilot reported that the airplane landed on the runway centerline and that he kept the nose landing gear off the runway as long as possible, but when the nose gear contacted the runway, the airplane veered right and off the runway. The airplane then continued to roll and skid several hundred feet until it nosed over.

Figure 3 – Airplane altitude, speed, and vertical speed

Figure 4 – Airplane ground track, roll angle, and flight path angle

According to the Cessna P210N Pilot Operating Handbook (POH), the airplane’s retractable landing gear is operated by an electrically-driven hydraulic power pack located behind the cockpit control pedestal. Hydraulic pressure is applied to actuator cylinders that extend or retract the landing gear and operate their respective gear down locks. A hydraulic pressure switch regulates electrical power to the pump motor to maintain the specified system pressure.

During normal operation, the landing gear is retracted and held in the fully retracted position by hydraulic pressure and, as such, the hydraulic power pack will occasionally cycle on/off during flight to maintain sufficient hydraulic pressure to keep the landing gear retracted.

During normal operation, the landing gear is extended into the down and locked position using hydraulic pressure supplied by the hydraulic power pack. Hydraulically actuated down locks are used to keep the main landing gear extended, and a mechanical hook is used to keep the nose gear extended.

The electrical portion of the hydraulic power pack is protected by a 30-amp “pull-off” type circuit breaker located in the circuit breaker panel. The POH cautions that if for any reason the hydraulic pump continues to run after a gear cycle completion (up or down), the GEAR PUMP circuit breaker should be pulled out to shut off the hydraulic pump motor and prevent damage to the pump and motor.

The hydraulic system fluid level is checked by referencing the dipstick/filler cap on the hydraulic power pack, which is accessed behind a snap-out cover panel on the right side of the control pedestal. The hydraulic fluid level should be checked at 25-hour intervals.

In the event the hydraulic power pack is inoperative, or its respective circuit breaker is pulled, the landing gear can be extended using a hand-operated emergency hydraulic pump (if hydraulic system fluid has not been completely lost). The hand pump is located on the cabin floor between the front seats.

The position of the landing gear is indicated by two lights (amber and green) located adjacent to the landing gear selector handle in the instrument panel. The amber landing gear position indicator illuminates when the landing gear is fully retracted. The green landing gear position indicator illuminates when the landing gear is fully extended, and their respective down locks are engaged.

The green landing gear down and locked indicator light has two “push-to-test” positions: depressed halfway (with throttle retarded and master switch on), the gear warning aural alert will be heard intermittently on the airplane speaker;, depressed fully, the green light should illuminate. The amber landing gear up indicator light has one “push-to-test” function; the amber light should illuminate when fully depressed. Both landing gear position indicator assemblies can be rotated to adjust the lens dimming shutters. An inoperable bulb can be replaced in flight by using the bulb from the remaining landing gear position indicator light.

The Cessna P210 series Service Manual states that a low level of hydraulic fluid can result in insufficient hydraulic system pressure and the continuous operation of the hydraulic power pack, which could result in failure of the electric motor and the inability to extend the landing gear using the hydraulic power pack.

In the event of a hydraulic power pack failure, the emergency hand pump draws hydraulic fluid at a lower level in the reservoir than the power pack and, as such, the emergency hand pump remains able to extend the landing gear if there is not a total loss of hydraulic fluid in the system.

The nearest aviation weather station was located at Aransas County Airport (RKP), Rockport, Texas, about 19.5 nautical miles southeast of the accident site. At 1453, the surface winds at RKP were 150° at 9 knots with 18 knot gusts. At 1553, the surface winds at RKP were 170° at 8 knots with 15 knot gusts.

According to a High-Resolution Rapid Refresh (HRRR) atmosphere model, at 1500, the surface wind at the accident site was 168° at 13 knots.

According to the Cessna P210N Pilot Operating Handbook (POH), the airplane’s retractable landing gear is operated by an electrically-driven hydraulic power pack located behind the cockpit control pedestal. Hydraulic pressure is applied to actuator cylinders that extend or retract the landing gear and operate their respective gear down locks. A hydraulic pressure switch regulates electrical power to the pump motor to maintain the specified system pressure.

During normal operation, the landing gear is retracted and held in the fully retracted position by hydraulic pressure and, as such, the hydraulic power pack will occasionally cycle on/off during flight to maintain sufficient hydraulic pressure to keep the landing gear retracted.

During normal operation, the landing gear is extended into the down and locked position using hydraulic pressure supplied by the hydraulic power pack. Hydraulically actuated down locks are used to keep the main landing gear extended, and a mechanical hook is used to keep the nose gear extended.

The electrical portion of the hydraulic power pack is protected by a 30-amp “pull-off” type circuit breaker located in the circuit breaker panel. The POH cautions that if for any reason the hydraulic pump continues to run after a gear cycle completion (up or down), the GEAR PUMP circuit breaker should be pulled out to shut off the hydraulic pump motor and prevent damage to the pump and motor.

The hydraulic system fluid level is checked by referencing the dipstick/filler cap on the hydraulic power pack, which is accessed behind a snap-out cover panel on the right side of the control pedestal. The hydraulic fluid level should be checked at 25-hour intervals.

In the event the hydraulic power pack is inoperative, or its respective circuit breaker is pulled, the landing gear can be extended using a hand-operated emergency hydraulic pump (if hydraulic system fluid has not been completely lost). The hand pump is located on the cabin floor between the front seats.

The position of the landing gear is indicated by two lights (amber and green) located adjacent to the landing gear selector handle in the instrument panel. The amber landing gear position indicator illuminates when the landing gear is fully retracted. The green landing gear position indicator illuminates when the landing gear is fully extended, and their respective down locks are engaged.

The green landing gear down and locked indicator light has two “push-to-test” positions: depressed halfway (with throttle retarded and master switch on), the gear warning aural alert will be heard intermittently on the airplane speaker;, depressed fully, the green light should illuminate. The amber landing gear up indicator light has one “push-to-test” function; the amber light should illuminate when fully depressed. Both landing gear position indicator assemblies can be rotated to adjust the lens dimming shutters. An inoperable bulb can be replaced in flight by using the bulb from the remaining landing gear position indicator light.

The Cessna P210 series Service Manual states that a low level of hydraulic fluid can result in insufficient hydraulic system pressure and the continuous operation of the hydraulic power pack, which could result in failure of the electric motor and the inability to extend the landing gear using the hydraulic power pack.

In the event of a hydraulic power pack failure, the emergency hand pump draws hydraulic fluid at a lower level in the reservoir than the power pack and, as such, the emergency hand pump remains able to extend the landing gear if there is not a total loss of hydraulic fluid in the system.

A Federal Aviation Administration airworthiness inspector conducted an onsite examination of the airplane. Based on wheel marks observed on the runway and grass easement, the airplane veered off the right side of runway 32R about midfield with all three landing gear extended.

The airplane continued about 330 ft in the grass easement before the nose landing gear strut and nose wheel separated from the nose gear casting. The airplane continued another 100 ft before it nosed over and came to rest inverted about 44 ft right of the runway edge and about 2,880 ft from the runway 32R displaced threshold. The fuselage, both wings, and empennage were substantially damaged during the accident.

There was no evidence of burnt wires or insulation in the airplane cockpit, or electrical arcing or thermal damage to the wiring between the hydraulic power pack and its respective circuit breaker. The 30-amp circuit breaker labeled GEAR PUMP was found tripped/pulled.

The green landing gear down and locked position indicator light did not initially illuminate when electric power was turned on. However, the green light illuminated after the bulb assembly was unscrewed and reinstalled.

The airplane was recovered to the ramp where it was hoisted by a crane to test the landing gear extension/retraction system. With electrical power turned on and the circuit breaker reset, the hydraulic power pack did not function when the landing gear selector lever was cycled between gear-up and gear-down positions. Examination of the hydraulic power pack fluid reservoir revealed that the fluid level was below the ADD level as indicated by the reservoir dip stick. Further examination of the hydraulic system did not reveal any evidence of a leak. When tested, the landing gear extended into a down and locked position using the emergency landing gear extension hand pump.