An Interesting GTSB (Greg Transportation Safety Board) Report

An Interesting GTSB (Greg Transportation Safety Board) Report

(Subject to revision)

On August 29, 2024, at approximately 6:30PM (EDT), the engine in the #33 Porsche 914 suddenly stopped as it was slowly driving away from the town green of Falls Village, CT. Hearing a large noise (discernable by nearby onlookers), the driver immediately disengaged the drivetrain via the foot clutch and car coasted to the side of the street. Initial attempts to restart the engine were met with a starter that would not rotate; attempts to push the car while the transaxle was engaged were met with full resistance. It was quickly determined that the engine had locked up.

After minimal roadside investigation, it was determined that the dry sump tank oil valve, which supplies oil to the engine oil pump, was in the closed position and it was obvious that the engine had been run without a supply of oil. As a result, the car was "flat bedded" back to Lime Rock Park and retained as a paddock display for the  remainder of the Historics race weekend.

The weather conditions at BDL (the closest reporting station) at the time of the incident were 10SM visibility with an overcast at 3600 feet (MSL), temperature 23 dewpoint 15 ("a nice day").

Background

Lime Rock Park's Historic Festival 42 was held from Thursday August 29 through Monday September 2, 2024. The weekend's events kick off on Thursday with a Festival Parade of both race and street cars through the hills of Litchfield County CT, ending with a gathering in the Falls Village town green. The cars are displayed in the green, with drinks and food vendors and a band while onlookers gather to look at the cars. Afterward, race cars return to Lime Rock Park to finish preparations for the race weekend.

Analysis

#33 914 successfully completed the parade route and arrived at the Falls Villge town green with the other cars. Upon arriving at the town green, its pilot chatted with onlookers about the #33 while making minimal preparations to secure the car so he could wander the green, meet with friends, and look at other cars. These preparations included turning off and removing the race car's master key, securing the car's ignition key (it uses a stock ignition lock), and closing the supply valve between the dry sump oil tank and the engine. This last step is done between sessions at the track to reduce the amount of oil that may drain back to the engine due to gravity; in excess, too much drainback could result in an engine case filled with oil (causing smoky startups) and in theory could possibly hydrolock the engine.

To avoid starting the engine with the oil valve closed, the team has developed a process where the master key is clipped to the closed oil valve's handle via a caribiner, reminding the driver to turn on the valve before inserting the master key. The ignition key is rarely, if ever, removed from the ignition lock.

However, due to concerns of either key being taken from the car while he was away, the driver put both the ignition and master keys in his pocket, yet still closed the oil valve.

Upon returning to the car to depart as the sky was darkening, the driver was again involved with onlookers discussing the car and was in a relative haste to get back to the track before dark (the car has no functioning headlights). The driver inserted both the ignition and master keys and started the car, without verifying that the oil valve was opened.

Upon idling away from the town green, at low speed and RPM in first gear, the engine suddenly seized due to oil starvation. It was only afterward, during the brief roadside investigation, that it was noted the oil valve was closed. The team decided to park the car for the weekend.

In addition to the master key clipping to the valve, the team provides oversight to such risk by the crew observing a mechanical oil pressure gauge in the engine compartment; this gauge is not visible by the driver in the normal seating position. Upon each engine startup a crew member will observe the mechanical gauge to confirm that oil pressure builds immediately. In this particular situation, however, the driver did the parade and town green solo, so there was no oversight of the mechanical gauge.

The driver is further provided engine oil pressure data as part of the gauge package, which consists of a large electrical tachometer and a Race Technology "DASH-3" LCD display. Oil pressure is part of that display.

However, this display has a significant shortcoming: it is an older design that takes 5-10 seconds to cycle through its startup procedures after engine start before it will display data. This is the primary reason for a crew member to watch the engine compartment mechanical gauge for oil pressure. As a result, it had become habit for the driver to not specifically check for oil pressure on the gauge when it came up, instead relaying on the crew reading the mechanical gauge, which in this case was not monitored.

Finally, while it is capable of doing so, in reviewing the configuration of the DASH-3 it was determined that a "low oil pressure warning" flashing LEDs was not configured on the digital display. It is unknown why that was not configured; probably a simple oversight, or maybe it was intentional to avoid nuisance notifications on startup (which require manual cancellation).

Probable Cause

The Greg Transportation Safety Board determines the probable cause(s) of this accident to be the pilot's failure to open the dry sump oil tank prior to departing from the Falls Village town green, resulting in oil starvation and engine seizure.

Contributing factors:

• Pilot distractions due to the event;
• Failure of the pilot to confirm oil pressure after engine start;
• Lack of process (checklists) to avoid such failure in unusual situations;
• Lack of active warning (flashing LEDs) of low engine oil pressure to the pilot;
• Insufficient process to provide crew oversight of driver errors.

Recommendations

The GTSB recommends the following:

• Reevaluation of the needs and effects of closing the valve for short periods, potentially reserving that for long-term/storage only;
• Ensuring that the master key is attached to the oil valve 100% of the time the valve is close (and providing for an alternate master key/handle in case the key is stolen);
• Provide for updated display/gauging/data acq that will properly warn driver of low oil pressure conditions (as well as other "park the car" situations);
• Driver to check for oil pressure upon every startup, regardless of the situation;
• Team to develop processes for driver oversight.

Findings

Personnel issues Incorrect action selection - Driver

Aircraft (general) - Incorrect use/operation

Aircraft Airspeed - Not attained/maintained

Personnel issues Scheduled/routine maintenance - Maintenance personnel

Organizational issues Adequacy of safety program - Operator

Organizational issues Oversight of operation - Team Owner

11/15/24 Update:

From the engine builder: "You may have dodged a bullet. I got the engine apart tonight. Looks like the bearing behind the cam gear is the one that locked up. So far everything looks useable. I will need to measure the block but nothing looks like it got hot. Engine was running good."

Whew!