Phoenix, AZ, USA
N9152V
MOONEY M 20G
The private pilot receiving instruction reported that, abeam the runway threshold on the downwind leg of the traffic pattern, he reduced engine power to idle to conduct a practice 180o power-off landing. The pilot maintained glide speed until about 40 ft above the ground then noticed that the airplane was slightly below the intended glide path. The pilot applied throttle to initiate a go-around; however, the engine sputtered and power did not increase. The pilot executed a forced landing short of the runway; the airplane touched down hard and bounced. The right main and nose landing gear collapsed, and the airplane came to rest to the right of the runway. The flight instructor reported that, upon the pilot's decision to conduct a go-around, he ensured that the throttle, propeller, and mixture were in the correct position, but made no reference to carburetor heat. During a postaccident examination, the engine was started, operated, and shut down normally with no anomalies noted. Data from the engine monitoring system revealed that, shortly before the engine lost power, it was operating at idle power for about 1 1/2 minutes, during which the cylinder exhaust gas temperatures were decreasing. At the end of the 1 1/2 minutes, in the engine rpm increased and the the exhaust gas temperatures showed a small spike, then continued to decrease. The rpm then decreased to zero, and the manifold pressure adjusted to barometric pressure, consistent with a total loss of power. The reported temperature and dew point at the time of the accident were conducive to carburetor icing at glide and cruise power settings. It is likely that the carburetor collected ice during the time the engine was at idle power. When the pilot increased power, the engine responded momentarily, but was unable to continue operation with the restricted airflow through the carburetor. The airplane's pilot operating handbook stated that full carburetor heat should be applied when reducing power for descent or landing.
On July 10, 2015, about 0900 mountain standard time, a Mooney M20G, N9152V, experienced a partial loss of engine power while on short final to the Phoenix Deer Valley Airport (DVT), Phoenix, Arizona, and subsequently landed short of the runway. The private pilot undergoing instruction and the certified flight instructor (CFI) sustained no injuries; the airplane sustained substantial damage to the right wing. The airplane is registered to a private individual and operated by the private pilot under the provisions of 14 Code of Federal Regulations Part 91 as an instructional flight. Visual meteorological conditions prevailed and no flight plan was filed. The private pilot undergoing instruction reported that when they passed the approach end of the runway on the downwind leg of the traffic pattern, he reduced power to idle to conduct a practice 180o power off landing. The pilot maintained glide speed until about 40 feet above the ground when the pilot observed the airplane was slightly below the intended glide path. The pilot increased power to initiate a go around, however, the engine sputtered and did not increase RPM. The pilot executed a forced landing short of the runway surface; the airplane touched down hard and bounced. When it settled back onto the ground, the right main landing gear and nose landing gear collapsed and the airplane came to rest to the right of the runway surface. The CFI reported that when the private pilot decided to conduct a go around, he looked at the throttle quadrant to confirm that the throttle was full forward and the propeller and mixture levers were also positioned correctly. A postaccident engine run was conducted by a mechanic and inspectors from the Federal Aviation Administration (FAA). The spark plugs were removed and examined; they displayed signatures consistent with a rich running engine. The spark plugs were reinstalled and an undamaged propeller was installed. The engine started without hesitation; after idling temporarily, the RPM was increased and a magneto check was completed with no abnormalities noted. The power was decreased to idle for two minutes to simulate a 180o power off landing. The throttle was abruptly increased to full power; it hesitated for a split second and went to full RPM for a couple minutes. This sequence was conducted twice with no anomalies noted. The engine was shutdown uneventfully. The engine data monitor download showed that shortly before the engine lost power, the engine was at idle for about 1.5 minutes; during which, the cylinder exhaust gas temperatures were decreasing. At the end of the 1.5 minutes, there was an increase in RPM and subsequent small spike in the exhaust gas temperatures before they continued to decrease. In addition, the RPMs continued to zero, and the manifold pressure adjusted to barometric pressure. At the time of the accident, the reported temperature was 29o C and the dew point was 7o C. According to the FAA carburetor icing Special Airworthiness Information Bulletin, the condition was conducive to carburetor icing at glide and cruise power settings.
The pilots' failure to apply carburetor heat during the approach for landing, which resulted in a total loss of engine power due to carburetor icing.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
