History of Flight
On September 22, 2017, at about 2157 Pacific daylight time, a Mooney M20E airplane, N34BE, collided with the ground on a densely populated street in Glendale, California, following a loss of engine power during en route cruise. The private pilot and passenger sustained minor injuries, and the airplane sustained substantial damage to the left wing and fuselage. The airplane was registered to Cleared Direct Aviation LLC. and operated by the pilot under 14 CFR Part 91 as a personal flight. Night visual meteorological conditions prevailed, and no flight plan was filed. The cross-country flight originated from Redlands Municipal Airport (REI) about 2130 and was destined for Bob Hope Airport (BUR), Burbank, California.
Earlier in the evening, the pilot departed from his base at Santa Monica (SMO) to pick up his passenger from a Fixed Base Operator (FBO) in Burbank. They then both flew to Redlands for an event, and the accident flight was the return leg. The pilot stated that ordinarily he would have serviced the airplane with fuel in Redlands, but the passenger needed to return to Burbank before the FBO closed at 2200. The pilot calculated fuel based on engine tachometer time and believed he had enough for the 30-minute flight with a 45-minute reserve.
After departing Redlands, the pilot climbed to and configured the airplane for level cruise at 4,500 ft msl, direct to Burbank. The flight was uneventful; as the airplane approached Burbank, he began a descent to about 3,000 ft msl. He reached the Rose Bowl (11 miles east of Burbank) at 2152 and made the first radio call to Burbank air traffic control tower. The controller directed him to enter the left traffic pattern for landing on runway 15.
About 90 seconds later, at about 2,500 ft msl (1,800 ft agl), the engine began to lose power. The pilot declared an emergency, and unable to maintain altitude, he pitched for best glide speed and initiated trouble-shooting procedures, including turning on the auxiliary fuel pump and switching to the opposing fuel tank. The engine did not respond. After consulting his handheld electronic navigation device's glide distance radius, he concluded he would not reach the runway. He looked for a suitable landing site; all highways and major streets were congested, so he elected to land on the darkest street he could see. As he approached the street, the left wing struck a tree, and the airplane spun around, coming to rest upright on the pavement at the entrance to an apartment complex parking lot.
Pilot's Fuel Management
The pilot purchased the airplane five months before the accident and had been tracking fuel consumption at each top-off. He used engine tachometer time in his calculations (the airplane was not equipped with a Hobbs-hour meter, totalizer, or similar) and concluded the airplane consumed on average 9.5 gallons per hour (gph). For planning he used 10.5 gph; on average he refueled after about 32 gallons were consumed. He stated that fuel gauges were generally not accurate, typically indicating 3/4 when full, and gauge needles bounced in flight, preventing accurate en route fuel judgment. He did not dip the tanks during preflight because he could not find a dip gauge for the Mooney, but he visually looked into the tanks before each flight to confirm fuel presence. For the accident flight, he visually confirmed fuel and used prior flight time calculations to estimate quantity.
The pilot last serviced the airplane with 34.7 gallons at San Gabriel Valley Airport (EMT) on September 16, 2017, at tachometer time 1,528.41 hours (the accident site tachometer indicated 1,532.64 hours, 4.23 hours elapsed). He supervised fueling and confirmed both tanks were filled to capacity, ensuring no air gap.
He provided fueling and tachometer records since purchase indicating consumption between 7.7 and 11.6 gph. In the 4.23 hours since last top-off, he flew from El Monte to Santa Monica (0.31 hours), Santa Monica to Oceanside round trip (1.51 hours), Santa Monica to Chino (1.01 hours), and on accident day flights from Santa Monica to Burbank and Burbank to Redlands (times not documented). During the landing approach into Burbank to pick up the passenger, he performed a go-around and was diverted to land on runway 8, then taxied the full length of the parallel taxiway to the FBO.
Post-Accident Examination
The airplane was examined at the accident site about 90 minutes later. No fuel odor was present, and no fuel was observed in either tank through filler necks. The fuel selector valve had been switched to "OFF" by first responders; its pre-accident position could not be verified. After recovery, damage was observed to the underside of the right tank, causing a breach at the inboard rib and lower spar cap adjacent to the drain valve. The left fuel tank was undamaged.
Examination of the left fuel tank revealed compliance with Mooney Service Bulletin (SB) M20-188A; the drain valve was intact and operated freely. The underside showed no streaks or fuel leak indications. The right tank had not complied with the SB; the original valve was found closed and operated freely, and did not leak when low-pressure air was applied. Interior tank sealant around the valve was cracked, degraded, and dry and chalky. Brown streaks were observed on the external underside skins emanating aft from the inboard wing doubler near the drain valve. Due to impact damage, pre-accident tank integrity, especially around the sump drain valve, could not be confirmed.
Engine and Tachometer Tests
Because wings were removed for recovery, a temporary fuel system was used to test the engine. A fuel container was plumbed to both left and right tank feed lines at the fuselage wing roots. The engine started and operated normally through its full speed range on each selector valve setting. No fuel leaks were observed.
The mechanical cable-driven engine tachometer and cable were removed and examined; no anomalies were noted. The tachometer was tested at an FAA-certified repair station. Its dial markings matched the correct tachometer for the airplane and engine combination per Mooney documentation. A series of test runs at 2,500 RPM for one-hour periods showed tachometer times incremented 1.01, 1.01, and 1.02 hours. Calibration tests at eight speeds showed the tachometer needle indicated accurately within expected tolerances. Disassembly revealed no anomalies.