Size Matters

13 Sep 19 7 Comments

This morning, I woke up to headlines about spilling coffee in the cockpit (thank you R and Mom) and so of course I had to find out what happened. The case was released yesterday in the British Air Accidents Investigation Branch S2/2019 Special along with a number of other interesting incidents.

The incident in question was on the 6th of February 2019 on a Condor scheduled passenger flight operated by Thomas Cook. The flight was scheduled to fly from Frankfurt, Germany to Cancun, Mexico in an Airbus A330-243. The first officer was flying the plane and the commander was Pilot Monitoring. The flight was over the North Atlantic Ocean, passing Ireland to the west. The flight crew served coffee to the crew which the captain then placed on his tray table as they were approaching a waypoint.

The AAIB incident says

At approximately 1620hrs, the cup was knocked over.

In my house, that’s code for, “I didn’t do it! At least I didn’t mean to do it.”

In any event, someone knocked the coffee cup over, spilling the hot coffee onto the commander’s lap and the centre console, dripping into the commander’s audio control panel (ACP1). They dried the console (and one presumes, his lap) quickly but the damage was already done, ACP1 began to malfunction. The commander soon found he couldn’t receive or transmit although he could hear the transmissions on the first officer’s speaker. The flight crew tried to isolate ACP1 but this couldn’t be done from the cockpit.

In the image above, you can see ACP1 where the two round lights are, to the right of the commander’s sheep-skin covered seat. ACP2 is on the right side of the centre console.

The ACP1 became very hot and the flight crew noticed an electrical burning smell before it failed completely. About twenty minutes later, the first officer’s audio control panel (ACP2) became too hot to touch and one of the buttons started to melt. Smoke began rising from ACP1. That’s when the commander decided they needed to abandon the planned flight. The two flight crew took turns using supplementary oxygen and they diverted to Shannon, Ireland.

By the time they landed at Shannon, the smoke had dissipated although there was a residual burning smell. The local media reported at the time that five people were taken to the hospital for smoke inhalation, which seems a bit odd considering the small amount of smoke which never left the cockpit.

Once on the ground, the two panels were removed and confirmed that both had failed. No further damage was found to have been contaminated by the liquid or the resulting electrical short.

There is, of course a cup holder in the Airbus cockpit which the commander could have used. But the cups that Condor use for that route are a bit too big and so, it’s hard to get them in and out of the cup holder. The result, of course, is that flight crew use the small table in front of them instead of struggling with the cup holder. The AAIB has recommended that serving the coffee with a lid secured on the top of the cup could have reduced the amount of hot liquid that spilled. I think sippy cups are a damn good idea.

An example of cup used in aircraft cup holder as a part of the AAIB report, in case we really believe that they get sippy cups.

The panels were replaced and the aircraft continued to Manchester to pick up new crew before continuing to its original destination of Cancun.

Of course, this isn’t the first time such a spill has happened. In fact, I’m told that this is exactly the plot to the 1964 film Fate is the Hunter. Maybe I’ll watch it this weekend and analyse the crash for next week!

Condor has since sent out a notice to all cabin crew that they must use cup lids on all routes and issued a flight crew notice to remind pilots to be careful with liquids. More importantly, they are considering sourcing and supplying “appropriately sized cups for the aircraft’s cup holders” which seems like the obvious action to take.


  • The IMDB entry for “Fate Is the Hunter” (1964) now references this real-life incident in the “Trivia” section for the movie.

  • The opening sentence took me straight back to “Fate is the hunter”, one of the best books on aviation in my view. I am surprised that such an incident can still happen today.

  • Such a simple thing, but with such broad ramifications. Electronics and water are not a good mix and many a computer keyboard has been lost to a spilled cup of coffee. In most scenarios, coffee on the keyboard holds relatively minor consequences because you don’t have to find a landing strip before you shut down your computer, but with an aircraft, the consequences are exponentially greater. Had they not been able to divert to Ireland, this situation could have take on much greater seriousness.

    One thing that I learned in the world of aviation was that you have to think ahead to the possibility that even a minor change in routine can have serious consequences. In the IT business, we have a Change Control Board which meets weekly to review proposed changes. If I want to make a change to the network backbone, the server team and the software folks can raise objections, if they feel that said change could negatively affect their area of responsibility. Conversely, I can object if a proposed change would have an adverse affect upon network performance. Even minor changes are presented. Here’s how it would play out if applied to this situation.

    The food service team would propose changing the size of the coffee cups. It would be noted that the cups would no longer fit in the existing cup holders. The engine team would pose no objection and the airframe team would pose no objection, but the avionics team would (hopefully) see the new level of risk posed by using cups which didn’t fit into the existing cup holders, and would be placed on a table instead of being kept more securely in the cup holder. The proposed change would be vetoed.

    Another change could be proposed involving lids on the cups and that would sail through CCB provided that a procedure was created requiring the Cabin Crew team training so that every one knew about the new restriction that came as a result of the change in cup size.

    But there’s another level to this; the human factors. Would a flight attendant actually refuse to serve coffee to a captain if they were out of lids? Would every flight crew member keep the lid in place, or would the lid be removed when the coffee was starting to get cold, in order to facilitate faster drinking? Never underestimate the ability of human factors to inadvertently derail even the most ironclad of procedures.

  • “The food service team would propose changing the size of the coffee cups. It would be noted that the cups would no longer fit in the existing cup holders.” That assumes working communications between the food service team and the flight crews; however, many corporations make communications between departments difficult. I also wonder whether the larger cups were slightly cheaper (e.g., a different manufacturer offering a low price to get their foot in the door). And relying on cabin team training also seems like a single-point-of-failure issue — leaving aside the human factors you raise.

  • Wait. They waited for 20 minutes after getting a burning smell to turn around ? Shouldn’t that warrant an immediate turn to an airport ? Why wait for actual smoke. They can problem solve on the way to the airport. If they find it not to be a cause for concern they can always turn back around to their original destination.

  • EASA issued Emergency Airworthyness Directive 2020-0020-E two weeks ago, which states: “Two in-service occurrences were reported involving inadvertent liquid spillage on the ENG START panel or ECAM Control Panel (ECP) on the centre pedestal in the flight deck on A350 aeroplanes. In both cases, the aeroplane experienced an un-commanded engine in-flight shut-down (IFSD) of an engine some time after the liquid spillage. Subsequent engine relight attempts were not successful. In both events, the flight crew performed a diversion and landed the aeroplane safely.” … “To address these occurrences, Airbus published the AFM TR defining a liquid prohibited zone in the cockpit, and the procedures to be followed in the case of inadvertent liquid spillage on the centre pedestal.” (The incident aircraft were A350-900 registered HL7579 and N508DN, according to Aviation Herald.)

    Liquid spills in the cockpit can do more than just take out the radio!

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