737NG tailwind limitations

[Low-bypass]

This sounds a bit strange to me,i had an argument with a capt of mine few weeks ago and we didn't agree on that.According to what i know it's 10 knots and i crosschecked on the FCOM 1 on our planes it says 10 knots,the capt said it's 15 knots and when i checked on the PDF format of my FCOM 1 in my Ipad it says 15 knots and really i'm confused as to what to follow.Anybody to clarify me on this?

[PPRuNe User 402506]

wich rev of the fcom you have? airplane is limited at 15kts, most of the companies keep it at 10 kts in general, and 15 in approved airfield.

[de facto]

Have you ever looked into your aircraft AFM?

[Denti]

You have to pay Boeing a bit more to get the 15kt tailwind limit. That can be done retroactively and the AFM of the plane in question will be amended. Most of our planes have a 15kts tailwind limit for take off and a 10kts limit for landings, but that will be changed soon to 15 kts for either landing or take off.

[Cough]

It depends on either what contract was set up with Boeing originally or if they were paid subsequently for the tailwind upgrade.

I've flown 737's with 10kt and 15kt within the same fleet. The AFM limitations should be consulted for details on the aircraft you are flying...

[TypeIV]

Some are 10 some are 15. If its 10, you can have it increased to 15 after paying some people in Seattle alot of money for some paperwork. In our company it is written on the norm. checklist. 10 is more fun, it allows you to make more visuals and circling due to tailwind

[N1 Limit]

Thanks a lot chaps for your valuable contributions i crearlysee that 15 knots is the figure to work with

[Voodoo 3]

Like the above, ours are limited to 15kts although some airfields we operate to, Kathmandu springs to mind, has a limitation of 10kts due to the nature of the approach.

[safetypee]

Tailwind operations increase risks above those for headwind operations (takeoff and landing); most are countered by general certification and operational requirements.
However, the aircraft certification requirements for tailwinds greater than 10kts require special clearance*; where granted they may be associated with specific limitations / guidance. Those which I have seen and used, were operator / location specific and should not be read across to other situations or operators without careful consideration. If it isn’t in the AFM, the operation is not certificated irrespective of ‘an ops manual’.

The aircraft certification will validate the aircraft handling characteristics, including engines; for landing that the aircraft can be flown accurately to the required touchdown point in the higher winds, and that systems operation is not compromised; e.g. squat switching and retarding devices. etc. This might not consider all cross wind / turbulence conditions.
The landing distance performance assessment (RTO perf also) might not be so rigorous. The normal flare time and flight characteristics might be used with simple extrapolation of distance with speed (GS).
However, in operations the ideal touchdown position might not be achieved as consistently as with head winds, due to the tendency to extend the flare / float, which has a significant impact on distance – very much more than a linear interpretation. Similarly any delay in using the retarding devices will have a large effect (N.B. RTOs).
Also consider the reasons for landing downwind and any ‘external hazards’. IIRC one night-time noise abatement procedure allowed 15kts tailwind, but the risk of overrun increased significantly as the majority of braking was on the portion of the runway used normally for touchdown and was heavily contaminated with rubber deposits – not ‘safe’ when wet.

* FAA AC 25-7 Flight Test Guide For Certification Of Transport Category Airplanes
Tailwind Takeoff and Landing - Wind Velocities Greater than 10 Knots.