Introduction

Aviation is a complex industry with numerous components working in unison to keep passengers and crew safe during flight. However, even with rigorous testing and maintenance, aircraft can experience intermittent faults or issues that are difficult to detect, isolate, and repair. These undiagnosed problems can lead to catastrophic crashes and mishaps, resulting in loss of life and property, as well as significant monetary losses.

In this blog post, we will examine five crashes in aviation caused by intermittent faults, or no fault found test results, other industry incidents, the costs of undiagnosed and undetected intermittent faults, and how patented Intermittent Fault Detection™ (IFD™) technology from Universal Synaptics can assist in solving these issues.

Aviation Crashes Caused by Intermittence Faults

1. Air France Flight 447: On June 1, 2009, Air France Flight 447 crashed into the Atlantic Ocean, killing all 228 passengers and crew on board. The investigation revealed that faulty airspeed sensors, coupled with human error, caused the accident. The sensors had intermittent faults, which led to inconsistent readings of airspeed and altitude. The investigation into the crash found that the aircraft’s pitot tubes, which measure airspeed, had become obstructed by ice crystals, causing the autopilot to disengage and the aircraft to enter a stall. However, the investigation also found that the aircraft’s stall warning system had not functioned properly, likely due to an intermittent fault, which had caused the pilots to misinterpret the situation and take incorrect actions that exacerbated the problem.
2. Malaysia Airlines Flight 370: On March 8, 2014, Malaysia Airlines Flight 370 disappeared while en route from Kuala Lumpur to Beijing. The search for the missing aircraft and its 239 passengers and crew continues to this day. The cause of the disappearance is still unknown, but it is believed that an intermittent fault or no fault found test result could be responsible for the aircraft’s disappearance.
3. Helios Airways Flight 522: On August 14, 2005, Helios Airways Flight 522 crashed in Greece, killing all 121 passengers and crew on board. The cause of the crash was traced back to a problem with the aircraft’s air conditioning system, which led to the crew becoming incapacitated due to lack of oxygen. The problem with the air conditioning system was an intermittent fault that had gone undetected, and hence unrepaired
4. TWA Flight 800: On July 17, 1996, TWA Flight 800 exploded in mid-air off the coast of Long Island, killing all 230 passengers and crew on board. The cause of the explosion was traced back to an electrical fault that had caused a spark in the aircraft’s fuel tank. The fault was intermittent and had gone undetected during routine maintenance checks.
5. Birgenair Flight 301: On February 6, 1996, Birgenair Flight 301, a Boeing 757-200, crashed shortly after takeoff from Puerto Plata, Dominican Republic, killing all 189 passengers and crew on board. The cause of the crash was determined to be a malfunctioning air data unit that provided incorrect airspeed information to the aircraft’s instruments, which was caused by an intermittent fault in the unit’s static ports.

Intermittent Faults In Other Industries

Aviation is not the only industry susceptible to intermittent faults.  Aerospace and automotive industries experience safety issues and catastrophic losses tied to the intermittent failure mode.

1. In 1996, the Ariane 5 disaster was caused by an undiagnosed intermittent fault. This rocket was launched by the European Space Agency (ESA) on its maiden flight, but it exploded just 40 seconds after liftoff. The investigation into the crash found that an intermittent fault had occurred in the rocket’s guidance system, causing it to send incorrect data to the rocket’s onboard computer. The computer then attempted to correct the error by moving the rocket’s nozzles, which caused the rocket to veer off course and break apart.
2. In 2005, Toyota Camry vehicles were suddenly plagued by acceleration issues. Drivers reported that their cars would suddenly accelerate without warning, causing them to lose control and crash. The cause of the problem was later found to be an intermittent fault in the car’s electronic throttle control system, which could cause the system to enter a “fail-safe” mode that would maintain the throttle at its current position, even if the driver tried to reduce speed by applying the brakes.

Costs of Undiagnosed and Unrepaired Intermittent Faults

The cost of intermittent faults per aircraft or system per year can vary widely depending on a number of factors, such as the age and complexity of the aircraft or system, the types of system components and wire harnesses that are affected, and the severity and frequency of the faults.

In general, intermittent faults can lead to increased maintenance costs, as well as downtime and reduced availability of aircraft, systems, and components. For example, if a fault affects a critical system, such as the engine or avionics, the aircraft may need to be grounded until the issue can be diagnosed and resolved. Additionally, intermittent faults may lead to increased inspection and testing costs, as well as the cost of repairing or replacing damaged systems.

While it is difficult to estimate the exact cost of intermittent faults per aircraft per year, some studies have attempted to quantify the cost of maintenance and downtime associated with various types of faults. For example, a study by the Federal Aviation Administration (FAA) estimated that the cost of a single unscheduled engine removal due to an intermittent fault could range from $30,000 to $200,000. Another study by the European Aviation Safety Agency (EASA) found that the cost of unscheduled maintenance due to avionics faults could range from $10,000 to $60,000 per event.

It is worth noting that the cost of intermittent faults is not limited to the direct costs of maintenance and downtime. Intermittent faults can also lead to indirect costs, such as the cost of increased spare purchasing to “swap” out intermittent components, cost of delays and cancellations, loss of revenue, and reputational damage.

The cost of intermittent faults per aircraft per year can be significant and can vary depending on a number of factors. While the exact cost is difficult to estimate, it is clear that the cost of intermittent faults can have a significant impact on the aviation and other industries and highlights the importance of preventative maintenance and advanced intermittent fault detection techniques.

Summary

Intermittent faults and no fault found test results can be challenging to detect using traditional testing methods. However, with the development of IFD technology from Universal Synaptics, it is now possible to detect these faults and issues before they cause catastrophic accidents. Prognostic identification of intermittent faults before they can cause catastrophic or expensive failures is vital, as is the quick and comprehensive identification of this failure once it has already wreaked havoc on a system, aircraft, or vehicle. IFD technology provides both prognostic and diagnostic capabilities through neural network monitoring of all circuits of a system, component, or harness. By constantly injecting low voltage signal into the aircraft’s wiring and monitoring all circuits in parallel, intermittent faults that are difficult to detect using traditional testing methods, are easily identified for precise identification and repair.

IFD technology is especially useful for aircraft that have experienced intermittent faults or have no fault found test results in the past. By using IFD technology, maintenance crews can quickly identify and fix potential issues before they cause accidents, ensuring the safety of passengers and crew.

In conclusion, the aviation industry has seen several crashes caused by intermittent faults or no fault found test results. The development of IFD technology from Universal Synaptics has revolutionized the way aircraft are tested, making it possible to detect and fix potential issues before they cause catastrophic accidents. By implementing IFD technology in routine maintenance checks, the aviation industry can ensure the safety of passengers and crew and prevent accidents caused by undiagnosed issues.

The patented Portable Intermittent Fault Detector™ (PIFD™) from Universal Synaptics has been inserted into all Boeing commercial Aircraft Maintenance Manuals (AMMs), and is the only approved wiring test set for the F-35 Joint Strike Fighter Global Program.