Spanair Aircraft Did Not Have Flaps Deployed; Not Necessarily the Cause of the Accident

The preliminary report is in, and it appears that the Spanair aircraft that crashed on takeoff last month did not have its flaps extended. While it’s not clear if this was actually the cause of the accident, if it were, it would be eerily similar to the crash of Northwest 255 more than 20 years ago, as Chris B first mentioned in the comments in my first Spanair post. So what exactly are flaps and why do they matter? I think it’s time for a brief tutorial. I encourage other to jump into this discussion in the comments section.

EC-GNY Spanair McDonnell Douglas MD-80At left, you can see a Spanair MD-80 taking off the right way, with its flaps extended for takeoff. But I should back up. What are flaps? If you look at the back half of the wing, you’ll see that there are hinges and then pieces of the wing tilted slightly downward. Those are the flaps, and what they do is create a larger surface area for the wing on takeoff. This helps create more lift at slower speeds, so basically the airplane can takeoff earlier than it would without the flaps. NASA has a simple but effective tutorial on this subject.

Airplanes can take off without flaps, but they just need to get going faster. So, if you have a really long runway, you might be ok. But hot weather also reduces lift, and different aircraft types need different distances to get in the air. So, it’s not cut and dry. I’m sure right now, the authorities are running the numbers to see what exactly happened here.

Oh, and in case you were wondering, there is a flap warning when they aren’t extended for takeoff, but it could possibly have been malfunctioning, ignored, or misinterpreted. We just don’t know, but we’ll find out soon enough.

(Photo credit: EC-GNY Spanair McDonnell Douglas MD-80 by David el Nomo via Flickr)

9 Responses to Spanair Aircraft Did Not Have Flaps Deployed; Not Necessarily the Cause of the Accident

  1. sntheorist says:

    So, as far as I know, the Spanair MD-80 that crashed was heavily loaded (i.e., all seats were taken + luggage etc.) + it was for sure a hot day in Madrid, so no flaps could certainly be an important factor in the crash.

  2. TR says:

    It sounds like this plane model has less room for error given the size of the wings, engine power and plane weight characteristics. Interested layman.

  3. CF says:

    TR – I’m not sure if that’s true. Anyone here have more knowledge on the subject?

  4. Steveee says:

    I think the loading is a factor also as I was reading that different planes have different flap settings for take off. Some more flap, some less. It was a fatal error, just like the Metro engineer that ran a stop light and ran into the freight train, a fatal error. In both cases they know what happened, but why may never be known. In both cases of course, really sad and a waste of life.

  5. Jf says:

    flap warnings can also be disabled intentionally, as i believe was the case in the detroit crash. it was typically done when taxiing out on one engine so that the combination of high power setting and no flaps (trigger for warning) would not fill the cockpit with noise. you’ll notice that nowadays, in the US anyway, flaps are always set to takeoff position prior to taxi out except in extreme weather conditions such as heavy snow.

  6. David says:

    Cranky old fellow, so sorry to disagree with you on this one. You are normally right on the money, but not this post. A normal load MD-80 on a normal runway (such as Barajas) that reaches V-1 with no flaps deployed equals a crash. Its a simple as that. Cheers.

  7. CF says:

    David – Thanks for the clarification here. I’m not sure that we’re necessarily disagreeing. The title of the post is parroting the initial report from the investigators which says that they are not yet ready to say that the lack of flaps caused the crash. So that’s why I wrote it that way. As I said in the body of the post, if you can get a “really long runway” then you could get airborne, but that’s where I left it.

    Now, where my knowledge ends is how long that runway would need to be at the temperature we saw in Madrid that day with the load onboard. Assuming what you say is true (I have absolutely no reason to doubt it), then it seems like the investigators should find it easy to determine the ultimate cause of the accident. Any idea why they’d hold back on that?

  8. Old Pilot says:

    The high aspect ratio wing of the MD-80 requires flap and slat extension for takeoff. Theoretically, you could probably get it off the ground without them given a ridiculously long runway, but the speeds required would be in excess of the max. allowable tire speeds.

    We must be careful not to attribute the crash to the failure of the warning system. It is still the responsibility of the crew to determine that the configuration is correct for the take off conditions. While we still don’t know the cause, we can say that many accidents like this have occurred due to interrupted sequences of events. This crew aborted one take off, returned for maintenance, then departed again. The real questions will be, did the flap/slat actuation system fail, did the cockpit indicator of flap and slat positions fail to read correctly, or did the crew fail to select the appropriate settings?

    The videos published seem to indicate that the aircraft rotated and flew in ground effect – the effect that occurs withing approximately one half wing span of the ground which alters the airflow and reduces the angle of attack, allowing the aircraft to fly. Climbing out of ground effect is impossible with the incorrect settings, and the aircraft stalls and settles to the ground.

  9. Steveee says:

    Thanks for the information Old pilot. Distraction seems to play a part in tragic situations like this. I remember reading many years ago about the cockpit recording that when the pilots were going through the take off check list, one pilot said “flaps” there was no answer from the other pilot.
    The plane then crashed on take off.

    The Metroliner train engineer was texting when he went through the red stop signal and ran into the freight train at 42 MPH. Never even hit the brakes.

    Both cases seemed to involve distraction with tragic results.

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