# Is this takeoff of a 767 in bad weather conditions a normal procedure?

In this video, a 767 takes off in bad weather conditions. The comments of the video aren't very professional, so I ask here:

1. Is this a legitimate takeoff?

2. Some comments say that this was a close takeoff. Some comments do point out that on rotate, you can see the end of the strip of the lefter runway. Was it airborne before?

• Holy cow... Look at the spoiler deflection during the takeoff run. I'm guessing that wasn't helping their takeoff distance. – reirab Oct 3 '14 at 15:13
• @reirab You're right but seems that spoiler deflection is normal on full Ailerons to the Right. airliners.net/aviation-forums/tech_ops/read.main/303976 – TesterMen Tester Oct 3 '14 at 15:18
• Yeah, I assumed that was the reason for it, but, still, that's a lot of spoiler deflection for a takeoff run. – reirab Oct 3 '14 at 15:23
• The strips that you can see underneath the aircraft during the rotation are touchdown zone markings: en.wikipedia.org/wiki/Runway#Runway_markings – reirab Oct 3 '14 at 15:26

Take-off within the crosswind limits is a normal procedure. From the video it's hard to tell what the crosswind was in this particular situation, so it is impossible to tell about the legitimacy of this take-off.

Rotation seems to be on the 1000ft marker, i.e. 1000 ft from the runway threshold. But in case of a displaced threshold the take-off distance available may be more than 1000ft from that point. It was airborne before the end of the runway.

• Given the aileron/spoiler deflection, it certainly seems that the crosswind was rather high, but you're right that there's no way really to tell exactly what they were. – reirab Oct 3 '14 at 15:47

Without having a better understanding of the actual crosswind there's no way to say whether that one was out of limits. If I had to guess I'd say it was close. I fly light aircraft, not commercial jets but as far as I know takeoff in a heavy crosswind is similar - you keep aileron into the wind, and a bit of forward pressure on the stick to make sure your wheels have good contact to the ground. During the roll you build up a bit of extra speed so when you are ready to rotate you get well off the ground quickly so you get some ground clearance, and also have better control authority. It looks to me that's what these pilots did.

Given the conditions it was never going to be a comfortable ride, I see nothing wrong with the take-off.

Assuming everything was within its limits since we can't prove otherwise and therefore a legitimate take-off, it's the captain's call whether to take-off or not.

Nevertheless, judging by the video, the precipitation seems far too severe to consider this take-off completely safe. Also, the crosswind might have been quite strong considering the open spoilers (also called airbrakes) caused by full left aileron being applied to compensate for the crosswind, which ultimately increases the take-off distance.

Furthermore, if it was a stormy cumulonimbus cloud, the take-off could have been delayed by half an hour, and the meteorologic conditions would have been much better in terms of precipitation (and it would avoid scaring all the passengers).

From my point of view the main problem with such take-off would be in case of a take-off emergency (like an engine flame out due to the intensive water ingestion) before V1, forcing the pilots to brake, risking a runway overrun due to hydroplaning.

They made it, but I don't think it was the smartest decision!

• "risking a runway overrun due to hydroplaning" - runway surface conditions are factored in as part of the V1 speed. The whole point of calculating V1 is to determine the speed at which the aircraft cannot be safely stopped on the remaining runway given the current weather and surface conditions. – Steve Kuo Oct 11 '14 at 19:43
• @SteveKuo True, V1 calculation takes into account runway conditions (and should give a good safety margin) but a significant amount of time can pass between V1 calculation and the actual take off. Such amount of time could be enough for meteorological conditions to deteriorate. So in the end it comes down to the pilots experience and sometimes that's just not enough... Take a look on point 5.5.1 from this paper of dutch aerospace laboratory. – paulo.filip3 Oct 21 '14 at 22:41
• Sorry, forgot the link. reports.nlr.nl:8080/xmlui/bitstream/handle/10921/758/… – paulo.filip3 Oct 22 '14 at 8:17

It looks like it was raining (a lot) with a pretty good crosswind. They probably loaded extra fuel for the weather and decided to rotate after Vr instead of exactly at Vr, thus using more runway. Wiggling the controls around didn't help the takeoff roll but it did keep the plane straight - usually a good thing.

As a passenger this would not have bothered me at all. Some years ago I was departing Hong Kong on Northwest, right in the middle of a typhoon. We sat at the threshold for 20-30 minutes, then the engines went to full power and we got out of there. The FA across from me said the flight crew told them to buckle in and stay seated for 20 minutes after takeoff, and she'd never heard that in her career. So obviously the pilot felt it was going to be a rough ride but he also felt it would not be a problem.

Landing back at the airport in the video would have been quite exciting, possibly requiring the Force in addition to redundant Cat IIIb autoland. But there's no requirement that you return to your departure airport if you have a problem - if there's another one 10 minutes away with better weather you go there instead.

• $V_1$ is the speed after which you are committed to take off, but not the speed at which you can actually take-off. Rotation speed is $V_r$. – Jan Hudec Oct 4 '14 at 11:58
• "[flight attendants would] stay seated for 20 minutes" - it's not that uncommon; I've been on flights like that a few time. The most recent was yesterday, flying from Chicago to New York; the pilot announced before takeoff that he had just come in from New York, and things were pretty choppy over the Great Lakes, so beverage service would be delayed because the flight attendants would be buckled in for about the first 40 minutes of the flight. – Pete Becker Oct 4 '14 at 15:01
• Interesting. Looks like my FA never worked the northeast routes then. If I recall, she preferred long-haul. – paul Oct 7 '14 at 8:48