N177MF177mf PITTS MODEL 12 · 2009

***This report was modified on January 26, 2016. Please see the docket for this accident to view the original report.***

On May 3, 2014, about 1945 mountain daylight time, an experimental amateur-built Pitts 12, N177MF, was substantially damaged in an off-airport landing near Bluffdale, Utah. The pilot/owner and his passenger received minor injuries. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no Federal Aviation Administration (FAA) flight plan was filed for the flight.

According to the pilot, he had recently purchased the airplane, and he and his wife planned to fly it from the purchase location in Washington state to their home airport in New Mexico. The first flight of the day initiated from Arlington Municipal airport (AWO), Arlington Washington, and terminated in a planned stop at Columbia Gorge Regional Airport (DLS), The Dalles, Oregon. That flight leg was uneventful, and the pilot reported that he topped off the fuel tanks at DLS. The airplane departed DLS, with the pilot's next planned fuel stop in the vicinity of Provo, Utah.

The pilot reported that he conducted the cruise portion of that flight at an altitude of 9,500 feet above mean sea level (msl). When the airplane was about 30 miles from Provo Municipal airport (PVU), Provo, the pilot began a gradual descent, and shortly thereafter, the engine quit. The pilot switched from the main tank to the auxiliary tank and attempted to restart the engine, without success. The pilot then turned his attention to selecting an off-airport landing site in an open field, and turned off all electrical equipment in the airplane. The airplane landed hard, and "flipped over on its back." The pilot exited, assisted his wife with her exit, and both walked away from the airplane because they smelled fuel. A passer-by arrived within about 15 minutes, and the local authorities were notified of the accident.

An FAA inspector visited the accident site within an hour of the accident, but did not note any obvious deficiencies that he could associate with the loss of power. The airplane was recovered to a secure location 2 days after the accident.

The 53-year-old pilot held a private pilot certificate with airplane single-engine, multiengine land, rotorcraft-helicopter and instrument airplane ratings. According to the pilot, he had approximately 3,868 total hours of flight experience, including about 8 hours in the accident airplane make and model. His most recent FAA third-class medical certificate was issued in February 2013, and his most recent flight review was completed in May 2013.

According to the pilot, he purchased the airplane in April 2014. Prior to his experience with the purchase of the accident airplane, the pilot had never flown a Pitts Model 12. His overall experience in the accident airplane make and model consisted of a 3-hour checkout with another individual the day prior to the accident, and then one flight leg (before the accident leg) on the day of the accident.

The airplane was a tandem cockpit biplane. The designated pilot's cockpit was the rear cockpit, and the pilot occupied that cockpit for the flight. The airplane was manufactured in 2009 and was registered in the Experimental – Exhibition & Air Racing category. According to information provided by the pilot, the airplane had a total time in service of 146 hours, and its most recent annual inspection was completed in June 2013. The engine had a total time in service of 596 hours, and had accumulated 146 hours since its most recent overhaul. Review of the maintenance records did not reveal any unusual conditions or maintenance actions.

The airplane was equipped with a Romanian Vendenyev M14 series radial engine. M14 engines were produced by the manufacturer in two series, both of which were carbureted: the 360 hp M14P and the supercharged 400 hp M14PF. An American engine facility, Barrett Precision Engines (BPE), developed several modifications for the M14 engines, including different pistons, different ignition systems, and fuel injection. BPE did not change the engine designations (M14P or M14PF) and did not independently develop or provide power or fuel flow charts for the engines it modified, in part because there were multiple permutations of BPE engine modifications.

Just before its installation in the airplane, the M14P engine was overhauled by BPE, at which time several significant modifications, including high-compression pistons and a fuel injection system, were incorporated. According to a representative of BPE, "the engine was not tested at our facility as we did not have a test cell for the M14 at that time," and the installation, testing and "fuel flow set up" of the engine would have to have been accomplished by another facility. Investigative efforts to determine whether, when, or by whom the testing and fuel flow set up were accomplished were unsuccessful.

The 1955 automated weather observation at PVU, located about 20 miles south southeast of the accident site, included winds from 190 degrees at 14 knots, visibility 15 miles, a broken cloud layer at 14,000 feet, temperature 23 degrees C, dew point 2 degrees C, and an altimeter setting of 29.84 inches of mercury.

The airplane came to rest inverted in a field. The FAA inspector who responded to the scene the night of the accident was only able to make a cursory examination of the airplane. Due in part to the darkness and the airplane attitude, the inspector did not note any obvious pre-impact deficiencies or conditions that would have resulted in the power loss.

Personnel from the recovery company noted that when they righted the airplane, about "4 to 5 gallons of av gas came pouring out of the bottom [main] fuel tank." They did not report exactly where the fuel exited from. The recovery personnel did not determine whether there was any fuel in the wing tank. The airplane was equipped with a smoke oil tank mounted near the main fuel tank. Neither the pre departure nor post accident oil quantity of that tank was determined, and the possibility that the smoke oil comprised a portion of the observed spill could not be discounted. As a result of those events and circumstances, the actual remaining fuel quantity at the time of the accident was not able to be determined.

The investigation was unable to obtain detailed design and construction information such as system schematics and component manuals. The airplane was examined in detail at the recovery facility several months after the accident. The upper wing had been removed as a unit for recovery and transport, while the lower wings were cut and fracture-separated from the fuselage. The cockpits were intact. The engine was displaced aft and canted nose-down, but remained attached to all the engine mounts. The three blade wood/composite propeller damage was consistent with little or no power being provided to the propeller at the time of impact. All components of the airplane and engine were accounted for at the recovery facility.

The engine was fuel injected, with a dual magneto ignition system controlled by two dedicated cockpit switches. Aside from crush damage to the underside, there was no obvious damage to the engine. The throttle/injector body was fractured and fracture-separated from the engine, and the throttle body placard identified it as an Airflow Performance brand "Experimental Fuel Control." Two fuel lines and the throttle linkage retained the throttle body to the engine/airframe. Throttle linkage continuity from the cockpits to the throttle body was confirmed, and the cockpit throttle controls moved synchronously through their full ranges.

All spark plugs were installed and intact, with one exception due to impact. All ignition leads remained attached to their respective spark plugs. All examined spark plug electrodes were consistent with near-new condition. The propeller was manually rotated, and thumb compressions were detected on all cylinders. The two separate magnetos and all the ignition harnesses appeared undamaged, but the systems were not tested, due to accessibility problems, and the low likelihood of a simultaneous dual magneto failure. Damage to the airplane, lack of design and construction information, and limited resources precluded a complete determination of the ignition system integrity or functionality.

The examination did not reveal any pre-impact mechanical deficiencies that could be associated with the power loss. Additional examination details may be found in the public docket for this accident.

The airplane was equipped with a Garmin GPSMap 496, which was removed and sent to the NTSB Recorders Laboratory for data download. The last flight record on the device occurred on May 3, 2014. The flight originated at DLS, covered 598.1 statute miles, and lasted approximately 3.5 hours; that flight was the accident leg. The flight prior to the accident leg was also captured by the device. That flight, which originated at AWO, covered 319.4 statute miles, and lasted approximately 2 hours. There was no recorded track data associated with any of these flights. Additional details may be found in the public docket for this accident.

Pilots Operating Handbook (POH) Information

A POH was found in the airplane. The POH cover page indicated that it was specific to the accident airplane by serial number, and was prepared by an individual whose website indicated that he is an airshow pilot who flies a Pitts S-12. The document consisted of 21 single-sided pages. The POH stated that the airplane had a total fuel capacity of 54 gallons, of which 53 gallons were usable.

The POH presented a table for five different engine power settings (Takeoff, Max Acro, Mid Acro, Normal Cruise, and Economy Cruise) with accompanying RPM, manifold pressure, and fuel flow values. The POH did not define any other applicable conditions such as altitude or temperature. The POH power setting table stated that it was for a "M-14P(PF) Engine and MTV-9-C/CL250(260)-29 propeller." The POH table stated that takeoff power was 400hp. The takeoff, normal cruise, and economy cruise fuel burn rates were 46, 16, and 14 gph respectively.

The POH "Procedures" section did not contain any information regarding fuel management, but did contain a seven-step checklist for "Inflight Engine Restart." That checklist included steps regarding glide speed ("100 MPH"), throttle setting ("OPEN 1/4 FULL"), and boost pump ("ON"). The checklist did not cite a specific fuel tank selection, or contain any reference to the engine primer switch.

Engine and Propeller Information

According to the engine logbook, the engine was a "VMP," model M14P, serial number K?012068; which appeared to match the engine data plate. According to the propeller logbook, the propeller was an "MT" brand, and cited as a model MTV-9-K-C/CL250-29.

Airplane Fuel System

The airplane was equipped with three fuel tanks; a wing-mounted auxiliary ("aux") tank, and fuselage-mounted main and header tanks. The main tank was plumbed directly to the header tank, which in turn was plumbed to the fuel selector valve and then to the engine. The aux tank was plumbed directly to the fuel selector valve.

The main tank was mounted forward of the forward cockpit, and was placarded as having a capacity of 36 gallons. The placard did not specify whether the quantity was the total capacity or the usable fuel quantity. The main tank was equipped with a rotary-style sight gauge graduated in fractions of tank capacity. The aux tank was placarded as having a capacity of 18 gallons. The placard did not specify whether the quantity was the total capacity or the usable fuel quantity. The aux tank was not equipped with any quantity gauging or indication system. The header tank capacity was not placarded or noted in the POH.

Post accident examination revealed that the main fuel tank was not breached, and retained its cap. The wing tank was breached due to impact damage, but retained its cap. The header tank did not appear to be breached by impact. The rod that connected the fuel selector handle to the fuel selector valve was fractured in overstress at the valve, consistent with impact damage. The valve was removed and disassembled; the valve was found ported from the header tank line to the gascolator, which was the position for the "Main" tank selection. Both the gascolator bowl and filter contained a negligible amount of undetermined contamination.

The investigation did not obtain any information regarding the calibration or accuracy of the fuel quantity indication system on the main tank. The investigation did not independently determine the actual capacities of the three fuel tanks, the actual unusable fuel quantity, or the actual pre-takeoff fuel quantity.

Re-Starting Fuel Injected Engines

According to FAA publication H-8083-25 "Pilot's Handbook of Aeronautical Information," disadvantages of fuel injection include "difficulty in starting a hot engine" and "problems associated with restarting an engine that quits because of fuel starvation."

Engine Information System

The airplane was equipped with two (one per cockpit) Grand Rapids Technologies brand Model 4000 EIS (Engine Information System) devices, which display a number of engine parameters, including fuel flow and fuel remaining. Fuel remaining is a derived parameter, calculated by the device by integrating fuel flow over time, and subtracting that from a pilot-entered initial fuel quantity.

The pilot referred to the device as a "totalizer." The devices are display only; they do not retain historical flight or operational information. The pilot reported that on the accident leg, he used the device's displayed information to monitor fuel flow and fuel quantity remaining. Integral to the fuel remaining calculation process, after the fuel upload at DLS, the pilot entered a fuel quantity of 53 gallons into the device prior to departure.

The investigation did not obtain any information regarding the calibration or accuracy of the fuel flow information provided to the EIS. Inaccuracies in EIS fuel flow values would affect EIS fuel remaining calculations.

Additional Pilot-Provided Information

Based on the pilot's statements, he departed DLS on the main tank, and remained on that tank for the climbout and the initial portion of the cruise segment. At some point he switched to the aux tank, and remained on that for 1 hour and 20 minutes. The pilot used the EIS to determine when there were about 2 to 3 gallons remaining in the aux tank, and then switched back to the main tank. After the power loss, the pilot switched to the aux tank. However, he did not recall whether he subsequently re-positioned the selector valve again, either to the main tank, or to the OFF position.

The pilot reported that during the flight, "the totalizer and the main gauge appeared to agree." He also estimated that at the time of the power loss, there was about 9 gallons remaining in the main tank, for a total estimated remaining quantity of about 11 gallons.

The pilot reported that the main tank fuel quantity indicator was "hard to see" from the rear cockpit. He also did not make any statements that indicated that he looked at that indicator subsequent to the power loss.

The pilot reported that at the time the power loss occurred, the engine was set at 23 inches of manifold pressure, 1,760 rpm, with the mixture leaned to "just under 12 gph." At that time, the airplane was at an altitude of about 8,300 feet msl, which was about 3,000 feet above ground level (agl). When asked what procedures and guidance he referred to after the power loss, the pilot responded that he used "normal emergency procedures" which he drew from his "prior training." After the power loss, the pilot switched on the fuel boost pump, and switched the fuel selector handle from the main tank to the aux tank. He elaborated that, given the airplane's altitude at the time of the power loss, he "did not have time to get the POH out," since he "knew" he only had a minute to attempt a re-start. The pilot reported that when the airplane reached an altitude of 2,000 feet agl, he turned his "complete focus" to landing the airplane, and did not distract himself with an attempted re-start. He estimated that 2 minutes elapsed between the power loss and touchdown.

In a written communication on May 8, 2014, the pilot stated that the engine "lost most if not all power," and that during the restart attempt "one time for about 2 seconds engine ran at full power."

In a written communication on May 10, 2014, the pilot stated that the power loss felt like a "'complete loss of ignition or fuel," and that the transition was from "smooth as glass to completely off instantly."

In a written communication on December 10, 2014, the pilot stated that the airplane "was operating perfectly with totally normal temps and pressures and just instantly shut down without even a hickup (sic). For what its worth it felt like either fuel was completely shut off or ignition was totally lost."

Fuel Planning Information

According to a representative of Jim Kimball Enterprises, which according to its website is a company that "specializes in antique aircraft restoration, replica aircraft design and construction, and kit aircraft component manufacture," including the Pitts S-12, and which was the company that built the airplane, the pilot's 3.5 hour flight was "about an hour longer than others planned for with that engine and fuel capacity."

The representative also stated that the main fuel tank had a capacity of 32 gallons, and was plumbed directly to the 4-gallon header tank.

Evaluation of the pilot-provided flight planning information revealed that the pilot used a climb fuel burn rate of 36 gph, and a cruise fuel burn rate of 12gph. His total calculated fuel burn was 44.8 gallons, over a total flight time of 3 hours and 25 minutes. NTSB calculations that used the pilot's waypoints and times, but used POH-provided fuel burn rates of 46 gph for climb and 14 gph for economy cruise resulted in a total fuel consumption of 51.3 gallons. Calculations that used the normal cruise fuel burn rate of 16 gph resulted in a total fuel burn of 58.3 gallons for the trip, which was 5.3 gallons more than the maximum usable fuel quantity.

Pilot's November 16, 2015, Input and Investigation Follow-up

The factual report for this investigation was posted to the NTSB web site in late October 2015. On November 16, 2015, the pilot sent the NTSB investigator an email stating that he had read the report and noted that the report's POH fuel burn citations were different than the values from a power setting chart that he had used for his flight planning. In further email communications, the pilot stated that the power setting chart he used was for the fuel-injected version of the engine, and "as the POH was based on a carbureted engine [he] thought it would be prudent and more accurate to use this chart for planning purposes." Review of the POH found in the airplane indicated that it was non-specific as to whether the engine was carbureted or fuel-injected.

Review of the power setting chart the pilot used indicated that it was for the "360hp M14P" engine, that it did not specifically state that it was for fuel-injected engines, and that the fuel burn rates were lower than those listed in the POH recovered from the airplane. Investigation fuel consumption calculations based on those rates indicated a trip fuel consumption of 44.4 gallons, which was close to the pilot's calculated flight planning value of 44.8 gallons.

Investigation communications with a representative of Jim Kimball Enterprises indicated that the individual whose name appeared on the cover of the POH found in the airplane was "one of the most experienced Model 12 pilots and mechanics on the planet." The representative added that that this individual "may have created the POH for a previous owner of the airplane," but that the representative was "not familiar with the document."