ERA14LA252

The pilot’s failure to attain the proper touchdown point during a no-flap landing to a wet, down-sloping runway, and the airplane's dynamic hydroplaning after touchdown, which resulted in a runway overrun. Contributing to the accident was a total loss of electrical power due to an alternator failure.

The airline transport pilot was conducting a personal cross-country flight in instrument meteorological conditions (IMC) when the airplane experienced a total electrical failure. The pilot elected to divert to a nearby airport, which had a 2,989-ft-long runway. After reporting the airport in sight, the pilot attempted a no-flap landing; however, the pilot reported that the brakes were ineffective, and he was unable to stop the airplane on the wet, down-sloping runway. He pulled the emergency (parking) brake handle and intentionally turned off the runway in an attempt to use an access road as additional distance to stop. The airplane subsequently struck a fence and other obstructions before it came to rest. During a postaccident phone call to the air traffic control facility that was handling the flight, the pilot stated the airplane landed "without brakes," "without flaps," and that they "landed long on the runway." Examination of the airplane's electrical system revealed that the alternator provided no output because the negative (ground) field brush was completely worn down to the braided lead, which became severed. The pilot should have received cockpit indications from the ammeter and from the low voltage warning light before the complete loss of electrical power. The pilot stated that despite "aggressive" application of brakes upon touchdown, the airplane would not slow down. It is possible that the airplane entered a state of dynamic hydroplaning on the wet runway, which would have rendered the brakes ineffective. Both the wet runway and lack of flaps on landing are factors which can significantly increase an airplane's landing distance. Given these conditions, the pilot should have more precisely controlled the airplane's descent angle throughout the approach in order to touch down within the shortest possible distance. It is likely that the decreased runway length available for landing, combined with dynamic hydroplaning due to the wet runway, resulted in the pilot's inability to stop the airplane on the runway.

According to the airport facility directory, 58M was an uncontrolled airport at a field elevation of 106 feet msl. Runway 13 was covered with an asphalt/aggregate friction seal coat in good condition, and was marked with basic markings in poor condition. It was also equipped with a precision approach path indicator which provided a 4.00-degree glide path, and runway end identifier lights. The runway was 2,989 feet long, and 70 feet wide. Obstructions were present on the final approach path in the form of 74-foot high trees located 919 feet from the runway, and 280 feet left of the centerline which required a 9:1 slope to clear. The threshold was displaced by 288 feet, and the runway slope was listed as being 1.5 percent toward the departure end of the runway. No-flap Approach and Landing According to the Airplane Flying Handbook (FAA-H-8083-3A), the inability to extend the wing flaps necessitates a no-flap approach and landing. In light airplanes a no flap approach and landing is not particularly difficult or dangerous. However, there are certain factors which must be considered in the execution of this maneuver. A no-flap landing requires substantially more runway than normal. The increase in required landing distance could be as much as 50 percent. When flying in the traffic pattern with the wing flaps retracted, the airplane must be flown in a relatively nose-high attitude to maintain altitude, as compared to flight with flaps extended. Losing altitude can be more of a problem without the benefit of the drag normally provided by flaps. A wider, longer traffic pattern may be required in order to avoid the necessity of diving to lose altitude and consequently building up excessive airspeed. On final approach, a nose-high attitude can make it difficult to see the runway. This situation, if not anticipated, can result in serious errors in judgment of height and distance. Approaching the runway in a relatively nose-high attitude can also cause the perception that the airplane is close to a stall. This may cause the pilot to lower the nose abruptly and risk touching down on the nosewheel. With the flaps retracted and the power reduced for landing, the airplane is slightly less stable in the pitch and roll axes. Without flaps, the airplane will tend to float considerably during roundout. The pilot should avoid the temptation to force the airplane onto the runway at an excessively high speed. Neither should the pilot flare excessively, because without flaps this might cause the tail to strike the runway. Approach Speed The pilot advised that he had flown the final approach to the runway at 75 knots indicated airspeed. Review of the Cessna 182S information manual revealed that normal landing approaches could be made with power on or power off, with any flap setting desired. Stall speed with flaps up was 40 knots indicated airspeed. According to the Airplane Flying Handbook (FAA-8083-3A); a speed equal to 1.3 times the power off stalling speed (VSO) of the airplane should be used. If VSO is 40 knots, the speed should be 52 knots. When the pitch attitude and airspeed have been stabilized, the airplane should be retrimmed to relieve the pressures being held on the controls. The descent angle should be controlled throughout the approach so that the airplane will land in the center of the first third of the runway. The descent angle is affected by all four fundamental forces that act on an airplane (lift, drag, thrust, and weight). If all the forces are constant, the descent angle will be constant in a no-wind condition. The pilot can control these forces by adjusting the airspeed, attitude, power, and drag (through the use of flaps or forward slip). Dynamic Hydroplaning According to the FAA, dynamic hydroplaning is related to tire inflation pressure. Data obtained during hydroplaning tests have shown that the minimum dynamic hydroplaning speed of a tire is 8.6 times the square root of the tire pressure in pounds per square inch. For an airplane like the Cessna 182S with a main tire pressure of 32 pounds, the calculated hydroplaning speed would be approximately 49 knots. According to the FAA, it is important to note that the calculated speed is for the start of dynamic hydroplaning, and that once hydroplaning has started, it may persist to a significantly slower speed. Examination of the wreckage by an FAA inspector revealed that during the runway overrun and impact with the fence, the airplane incurred damage to propeller, engine, engine mount, firewall, nose landing gear, engine cowlings, fuselage, left wing, empennage, horizontal stab, and vertical fin. Further examination revealed that the battery was discharged, there was no evidence of a lightning strike, and the brakes were functional. Examination of the key components of the J-Box which included relays, fuses, and the ACU, did not reveal an evidence of failure or malfunction. The coil resistance of each relay was found to be within normal parameters, and the bus fuses were not blown and were in good condition. The low voltage function of the alternator control unit when tested also provided a discrete signal to the avionics display when the bus voltage dropped below 24.5 volts. Testing of the alternator revealed that there was no output from the alternator and system voltage was at battery level. The field voltage from the ACU was at full field condition indicating that there was a possible problem with the alternator. This was confirmed when field resistance between the field terminal and ground was measured and found to be an open circuit. Upon disassembly of the alternator, it was noticed that the negative (ground) field brush was completely worn down to the braided lead that connects it. There was evidence that the brush lead (which is embedded into the carbon brush body) was actually riding on the slip ring and conducting until the braid finally wore through. There was also evidence that the braid was riding on the copper slip ring because of the deep groove that was worn into the slip ring. The positive brush was also worn, and it was estimated that approximately 40 percent of the brush remained. The brush springs were removed and inspected and no defects were found. To verify the integrity of the rest of the rotor assembly the resistance of the rotor winding was also measured at the slip ring and was found to be 12.2 Ohms which was within the normal range. The National Weather Service Surface Analysis Chart for 0800 EDT (1200Z) for the area depicted a stationary front extending over Maryland into West Virginia, and western Pennsylvania and extending along the route of flight, with the accident site located immediately north of the frontal position. A small "bubble high" pressure system at 1017-hectopascals (hPa) was located over the Pennsylvania and Maryland border in the vicinity of the accident site. The station models indicated light winds less than 10 knots, overcast sky conditions with rain, fog, and/or mist were over the region. Clear conditions were reported over North Carolina in the vicinity of the destination airport. The National Climatic Data Center National radar mosaic for 0810 indicated an extensive band of weather echoes extending over the area Pennsylvania and Maryland and extended over the flight track and the Elkton area. Cecil County Airport (58M), Elkton, MD, did not have any weather reporting capability. The closest weather reporting to the accident site was from Phillips Army Airfield (APG), Aberdeen Proving Grounds, Maryland, approximately 11 miles southwest, and an elevation of 57 feet. The airport reported the following conditions surrounding the period: At 0754, winds were calm, visibility was 6 miles in mist, a broken cloud deck was present at 6,000 feet, it was overcast at 11,000 feet, the temperature was 16 degrees C, the dew point was 18 degrees C, and the altimeter setting was 30.00 inches of mercury. At 0856, th