0:Cruise Control Home
2:What is Cruise Control?
4:Functional aspects
5:What is Sudden Acceleration?
6:Incidence & Examples
failure mechanisms
8:Discussion of Failure Mechanisms
9:Links & References
Return to 6

A Note on Automobile Cruise Control Faults and Sudden Acceleration

by Dr Antony Anderson C.Eng FIEE

Section 6: Additional notes : Examples of intermittent failures on control systems outside the automobile industry

  1. Computers cause electronic cat flap latch to malfunction
  2. Transient magnetic fields produced by an electric drill alter second hand of an electric watch by 10 seconds
  3. Uncommanded operation of powered Wheelchairs.
  4. Geomagnetic storm blacks out Quebec
  5. Uncommanded release of munitions from a Navy jet landing on the aircraft carrier U.S.S. Forrestal
  6. A DC 10 Autopilot was disrupted during final landing approach by a battery-powered CD player
  7. Black Hawk Helicopter knocked out of the sky by radio waves.
  8. Chinook Mark II Helicopters experience spurious engine accelerations and decelerations
  9. Washington State Ferries replace "sail by wire" electronic control system with pneumatic controls
  • Computers cause electronic cat flap latch to malfunction. Computers used in a room close to a door fitted with a high-technology (magnetic) cat flap caused the latches on the cat flaps to rattle continuously whenever Windows was loaded or a Windows application run. (From the New Scientist magazine, 7th May 1997)
  • Uncommanded operation of powered Wheelchairs. The U.S. Food and Drug Administration's   FDA Consumer Magazine  May 1995 reported that  a man in a powered wheelchair was seriously injured when his chair rode off a cliff at high speed. He was several miles from a radio tower and three blocks from a busy road, where mobile radios were likely in use. The FDA subsequently tested powered wheelchairs in its laboratories after receiving reports of a number of other malfunctions and found that the wheelchairs' brakes would release and the wheels would begin turning in relatively low-strength electromagnetic fields. A police radio held about a meter away (3 feet, 4 inches) could cause some wheelchairs to move.

  • Residents in Hobart Tasmania trapped in their garages when radar on aircraft carrier USS Carl Vinson affected garage door remote controllers.

  • "Hobart in Tasmania suffered an unusual blight earlier this month. Residents all over town found themselves trapped in their garages when the remote controls that operate the garage doors suddenly failed to function. Roll-a-door companies were flooded with calls from angry garage owners and were at first completely nonplussed by the problem. Then the explanation emerged: the aircraft carrier USS Carl Vinson had just cruised majestically into the town’s docks, equipped with navigational radar employing the same frequency as the remote controls for the town’s garage doors. According to the local newspaper The Advocate, an apologetic Lieutenant Dave Waterman, the ship’s public affairs officer, said that the problem would only occur when the ship was arriving and leaving." (New Scientist, 24th April 1999, page 100)
  •  Geomagnetic storm blacks out Quebec

  • Every 11 years violent storms on the surface of the Sun cause massive amounts of energy – in the form of protons and electrons – to be thrown out into space. After a few days, this energy reaches Earth, interferes with the planet’s magnetic field and generates huge currents – particularly in the polar regions. These induced currents can subsequently induce massive surges in (power distribution) transmission lines, damaging transformers and causing high-amplitude harmonics. In the space of just 2 minutes in March 1989, six million people in Quebec, Canada, suffered a complete blackout because of a severe storm from space. In the UK the problems were less severe, but some were experienced (see Electrical Review, 20 July 1999). 
  • NASA Reference Publication 1374 “Electronic System Failures and Anomalies Attributed to Electronic Interference” July 1995  lists a number of non-space examples of electronic system failures, for example:
    • Uncommanded release of munitions from a Navy jet landing on the aircraft carrier U.S.S. Forrestal off the coast of Vietnam (1967) struck a fully armed and fuelled fighter on the deck. The results were explosions and the deaths of 134 sailors and severe damage to the carrier and aircraft. This accident was caused by the landing aircraft being illuminated by carrier-based radar and the resulting EMI sent an unwanted signal to the weapons system. (Source: NASA)

    • A DC 10 Autopilot was disrupted during final landing approach by a battery-powered CD player operated by a passenger in first-class in February 1993. To prevent the aircraft from crashing after suddenly veering off course, the pilot had manually to take control. (Source NASA)

  • Black Hawk Helicopter knocked out of the sky by radio waves. The Boston Globe  8 November 1987 reported that "The Army’s most advanced helicopter to carry troops into battle can be knocked out of the sky by routine radio waves from microwave towers, radio antennas and radars according to Pentagon officials and documents. Investigators believe that such radio waves made five of the Army’s UH-60 Black Hawks nose dive into the ground since 1982 killing 22 servicemen." According to the Globe, Navy Sea Hawks, which had improved protection against electromagnetic interference did not appear to suffer from the same problem. Because Electromagnetic Interference (EMI) leaves no “fingerprints”, the Army has been unable or unwilling to cite it as a cause of any other 29 Black Hawk accidents that have killed 48 servicemen since 1980. Shielding the Army Black Hawks to Navy standards would be “very costly,” Army officials said. [Army Blackhawks were however later modified.]
  • Chinook Mark II Helicopters experience spurious engine accelerations and decelerations. April 1994 onwards. Royal Air Force (RAF) Pilots on British Chinooks fitted with FADEC (Full Authority Digital Engine Controls) discovered that the Chinook's engines sometimes accelerated or decelerated suddenly and without warning. A Squadron Leader at the main UK Chinook depot, RAF Odiham, later told an RAF Board of  Inquiry: "The unforeseen malfunctions on the Chinook HC2 of a flight critical nature have mainly been associated with the engines control system FADEC. They have  resulted in undemanded engine shutdown, engine run-up, spurious engine failure captions, warnings in the cockpit and misleading and confusing cockpit engine indications". 

  • On 2 June 1994, an RAF Chinook Mark 2 helicopter, ZD 576, crashed on the Mull of Kintyre. All those on board the aircraft were killed in the crash and the aircraft sustained catastrophic damage. The cause of the accident was never confirmed, but the RAF Board of Enquiry concluded that both pilots were negligent.  A Parliamentary Select Committee was appointed to consider the justification for the RAF Board of Inquiry findings and interviewed expert witnesses. The Select Committee reported that "although no trace of any mechanical fault, other than a defective radar altimeter, was found by the Air Accidents Investigation Branch inspector, he was unable to dismiss the possibility of an undemanded flight control movement, an engine run up or a control jam having occurred. Any of these events could have had a serious effect upon the crew's ability to control the aircraft." They concluded: "we consider that it could not be said that there was absolutely no doubt whatsoever that some mechanical failure had not caused a loss of control of the aircraft....It is not our role to determine the likely cause of this accident, and indeed on the evidence which we have heard and read it would be impossible to do so. We are nevertheless satisfied, on the evidence before us and against the standard of  "absolutely no doubt whatsoever", that the Air Marshals were not justified in finding that negligence on the part of the pilots of ZD 576 caused the crash." 
  • Washington State Ferries replace "sail by wire" electronic control system with pneumatic controls (IEE Spectrum Vol 27, no 2 February 1990 page 54. The six ferries in the Issaquah class fitted with electronic control systems suffered a series of intermittent faults - ferries rammed docks or moved away from them even though no commands were given. In some instances a ferry shifted from forward to reverse with no warning. Eventually the ferries were retrofitted with hybrid electro-pneumatic control systems and, since then have performed flawlessly. The problems were caused by shoddy electronic control system design.

Antony Anderson
February 16th 2003