An A330 on Cathay Pacific (CX) Flight 780 experienced un-commanded power changes causing the crew to land at an excessive speed nearly double the normal approach speed. The normal speed at their weight was reported to be 130 knots, the aircraft touched down at 239. The Rolls Royce Trent 700 engines are controlled by Full Authority Digital Engine Controllers (fly by wire). Throttles that do what they want despite the position selected by the operator; starting to sound familiar? Toyota maybe? Toyota announced today they are going to do an expansive test on their Lexus version of an SUV, I suspect they got a nudge. Quick action; I wonder if an extensive test will be done on fly-by-wire applications?

Unconnected to A330 problems of late? Maybe, maybe not; I think not. The FADECs are integrated into the ADIRU’s (aircraft computers) that control every aspect of flight. In the recent control excursions the pitot system has been blamed (AF, NWA, etc) and in the case of the QANTAS excursions the angle of attack system (AOA). Now we get FADEC (duel, very unlikely) failures. There is not a single point of failure; unless you dig a bit deeper and analyze where the information is processed and acted upon. The ADIRU #1. How is engine thrust related? If the ADIRU senses the aircraft approaching stall; taking input from speed (pitot) or angle of attack the engines will be directed to over-ride the pilot and run power up and if the AOA spikes the flight controls will be directed to push negative g. Ah Ha!

Remember the engines on Sully’s A320 would have still produced thrust, probably allowing him to reach an airfield. However the FADECs over-rode the crew and shut them down. Humans are smarter than computers, they understand the unquantifiable; for example it is better to burn engines up then go for a swim.

Back in the day, when we fought an F-16 slow we didn’t fight the aircraft (we’d loose) we fought the computer. It would over-ride the pilot exposing him to a guns shot. The FA-18 was different (also fly-by-wire); if you wanted to fly zero airspeed it would let you, the pilot had the over-all control. Not that I haven’t witnessed a fight for control between an ex A-7 pilot and his brand new F-18 (Hornet does a hands off catapult launch) off the cat. However, in general the Navy wanted the pilot to be the final arbiter. Personally I agree.

Following the tragic loss of Air France 447, the published EASA (European Aviation Safety Agency) fix for the Airbus 330 was to replace the Thales pitot systems with Goodrich versions.  Pitot systems are a critical flight instrument system that measure indicated airspeed of an aircraft.  Here is the problem: the Jetstar A-330 that just experienced bad input to ADIRU #1 had the Goodrich systems installed.  As I have pointed out in past articles the single point of failure, in my opinion, is not the pitot system it is the ADIRU #1.  The air data inertial reference units are the process point for the various inputs; airspeed, angle of attack, etc.  Two other ADIRUs (#2 and #3) also collect the same data.  The fly by wire system is designed so that the three units communicate with each other and if one unit’s data is out of parameters it is dropped from the overall system.

The Australian Transportation Safety Board’s (ATSB) initial finding, on Qantas Flight 72’s A-330 incident, determined it was a false angle of attack input passed by ADIRU #1 to the primary flight computer that caused the subsequent loss of control and injuries.  ADIRU #1 would not automatically deselect, even after the flight crew switched the system to ADIRU#2.  It sent flawed inputs to the flight computer which caused the fly by wire system to overstress the airframe with spurious inputs.  Procedures were issued by the EASA and yet on a subsequent Qantas flight they failed to override ADIRU #1.  New procedures were then issued by the EASA to de-energize ADIRU #1 to prevent it from passing spurious data to the primary flight computer.   The European Aviation Safety Agency (EASA) issued two Emergency Airworthiness Directives (EAD) involving the ADIRU in December and January following the Qantas incidents.

In light of the ATSB’s findings and EASA issued procedures, I was totally confused by the focus on the pitot system after the Air France 447 accident.  The ATSB made it very clear that it was a separate system, the angle of attack system, which caused the QF 72 upset.  In short, it was my opinion that they were treating the symptom not the cause.  My opinion has not been swayed that it is the ADIRU #1 that is the common denominator in these incidents.  The recent problem with the Goodrich system seems to verify this.  Since it is apparent that the fix was not a fix; the question remains.  Is the A330 safe?

Alain Bouillard, leading the investigation into the June 1 crash for the French accident investigation agency BEA, says the sensors, called Pitot tubes, were not the only factor.
He says “it is an element but not the cause.”

With this statement I agree; and the unstated cause? Weather would be an easy explanation, however Mr. Bouillard has already stated the aircraft remained intact. That makes the weather an “element” not cause. What was the cause? The evidence points to a loss of control.

Putting the issue of whether the aircraft broke apart or not aside, the question then becomes what caused the loss of control? If the aircraft was intact then either the crew lost control or the fly by wire system failed. Two very similar incidents have happened with the Airbus 330 since AF-447. In both these recent incidents the crews maintained control and the backup fly by wire system functioned.

Therefore we must look for more data points. Qantas Flight 72 provides, in my opinion, a very plausible explanation. QF-72 experienced un-commanded pitch events caused by ADIRU #1 (Air Data Inertial Reference Unit) reacting to spurious angle of attack inputs according to the ATSB (Australian Transportation Safety Board). This event caused a loss of control to the crew, twice. The second time after they complied with the emergency procedures designed to prevent it, again according to the ATSB.

Another statement I agree with, is that if they do not find the Black Boxes, then the cause will not be definitively known.

After reading the Australian Transportation Safety Board’s (ATSB) preliminary report I don’t see how it can be. The ATSB report identifies spikes in Angle of Attack (AOA) as the cause of the upset of QANTAS (QF) Flight 72, not airspeed. Below is the timeline of QF-72: Continue Reading

The European Aviation Safety Agency (EASA) issued two Emergency Airworthiness Directives (EAD) involving the ADIRU in December and January. An EAD is different from the bulletin that was issued on the pitot system; an EAD is an immediate requirement as opposed to a recommendation. The Air France pilots union has told its members to refuse aircraft that have not had the pitot systems replaced in accordance with the bulletin. However the critical link remains the ADIRU; the two EADs deal with erroneous information being sent by the ADIRU causing severe in flight upset in the case of QANTAS Flight 72. Continue Reading

Recent press releases are pointing to the pitot system bulletin recommending replacement as the probable cause for the crash of Air France 447. The A 330 series aircraft has 3 pitot systems; two are electronic and one is mechanical (tubes). A recent advisory to replace one of the systems still doesn’t explain the total failure of the fly by wire system IMO. Continue Reading

Determining the cause of an aircraft lost at sea is a very difficult process; with deep water, currents and the distant locations, sometimes the cause cannot be definitively determined. My Memorial Day post is an example; we never found a single piece of Iron Claw 606, even after searching the area for days. Modern technology has helped in the process; ACARS (Aircraft Communication Addressing and Reporting System), satellite links, and modern radar tracking gives us a starting point. Continue Reading

LCDR Leland C Shanle Jr. USN (Ret)

Chip was born and raised in St. Louis Missouri. He attended Chaminade College Prep Class of 1977. After High School he joined Naval ROTC at the University of Missouri, Columbia. Upon graduation in December of 1981, he was commissioned an Ensign in the United States Navy. A month later he married Laura L Cantrell and they set out on their Navy adventure together.

After completing Aviation Indoctrination at Naval Air Station (NAS) Pensacola, Chip transferred to NAS Corpus Christi (VT 27) for primary flight training in the T-28B Trojan. Achieving jet grades he was next assigned to Training Squadron 4 (VT 4) back at NAS Pensacola. He successfully completed the Strike syllabus flying and Carrier Qualifying in the T-2B Buckeye then the TA-4J Sky hawk.

His first Fleet Squadron was VAQ 136 flying the EA-6B Prowler from the deck of the USS Midway, CV-41. Carrier Air Wing Five (CAG 5) was forward deployed on board CV-41 in Japan. While attached to VAQ 136/CAG 5 he flew missions in operation EARNEST WILL protecting US Flagged tankers in the Persian Gulf. At sea nearly continuously for the late 80s the Midway was the point carrier during the end game of the Cold War.

Returning to the United States in early 1990 he was assigned to Training Squadron 21 at NAS Kingsville as an Advanced Strike Flight Instructor. Flying the TA-4J Sky Hawk the instructors of VT 21 taught the Student Naval Aviators the art of war, in high speed fighter/attack aircraft, as well as how to find and land on the pitching deck of an aircraft carrier.

In 1993 he was re-assigned to the EA-6B returning to the Fleet as a Department Head for the VAQ 137 Rooks. VAQ 137/CAG 11 took part in operation DENY FLIGHT, Chip flew 40 missions from the USS America (CV 66) over war torn Bosnia. The America transited the Suez Canal in support of US Forces in Somalia before returning to the Aegean Sea and finally the United States.

After de-establishing VAQ 137 he transferred to the VAQ 135 Black Ravens on board the USS Lincoln CVN 72). After a quick turn around VAQ 135/CAG 1 deployed to the Persian Gulf flying missions over Iraq in support of OPERATION SOUTHERN WATCH. Chip was designated an Air Wing SEAD Strike Lead for CAG 1, and flew another 40 missions.

Chip’s last set of orders took him to Naval Weapons Test Squadron at Point Mugu (VX 30). As head of the QF-4N program for VX 30 he flew as a test pilot and fleet adversary pilot, and was honored to become a full member of the Society of Experimental Test Pilots. Leading Detachments from Puerto Rico in the East to Okinawa in the West, he had “a hoot” chasing around the young guys in the old F-4N and F-4S Phantom IIs.

Closing out his Naval Aviation career in 1998 with 600 carrier landings (200 night) on 11 different carriers; Chip, Laura and their 4 kids moved back to St. Louis. After being furloughed from a cargo carrier (Kitty Hawk) he settled in at American Airlines in 1999.

His former CO of VX 30, Captain Dave Kennedy, got him involved in the movie industry that same year. Chip was an aviation/military technical advisor on 5 major motion pictures (Pearl Harbor, Behind Enemy Lines, xXx, The Day After Tomorrow and Stealth). Helping to re-write scripts got him started as a writer. Project 7Alpha is the first in a series entitled American Aviators. Vengeance the next book in the series is scheduled for release soon.