Good point, Andrew. There's often an increased climb angle to go with increased performance but that angle is more often established after rotation when there's ground clearance available. Still, perhaps tail strikes are more likely if the pilot is planning a steep climb angle and inadvertently establishes that angle on rotation.

Also, in response to Mark W, United is bound by our legislative reporting requirements independently of its internal or FAA reporting requirements, so an immediately reportable incident would have to be reported to ATSB even if UA or FAA policy didn't require that. Usually there isn't much discrepancy but it's still our law that UA and crew have to comply with.

Thanks Stefan. Any idea why?

The point I was making is ICAO / IOSA standards from the relevant ICAO Annex, from which the Transport Regulations are derived lists "ground contact during landing or takeoff, including tail strike/over rotation and pod or wing strike" as an "operational occurence" - it is not an "immediately reportable" incident.

The crew follow their Policy and Procedures Manual with regards to Safety Reporting - which will be wholly to their carrier (the Flight Safety Department) not to outside agencies.

It is the carriers responsibility to make the assessment as to what is or must be reported, and if the requirement exits on United's Ops Spec for operations to Australia that they must independantly report any incidents to the ATSB (ie not via Annex 13 conventions [to NTSB to ATSB] because of Australian Law), then they will do so.

My experience with tail strikes is few are pilot technique - most are environmental and in aircraft like the B747, as flight crew you are not normally aware that it has occurred until ATC or another aircraft notify you - or more usually, the F/A's seated at the back call though a "loud bang" on take-off, to the flight deck during the sterile period.

The ATSB is investigating -

http://www.atsb.gov.au/publications/...-2010-029.aspx

N128UA departed SYD today at 1045 as UAL9918

There's an echo from post 33: http://yssyforum.net/board/showpost....0&postcount=33

:confused:

And went to RKPK. See http://flightaware.com/live/flight/U...016Z/YSSY/RKPK

Repairs/inspections there?

Seoul is a heavy maintenance facility for United. It went directly the for a permanent repair. A temporary repair was done in Syd by QF sheetmetal personnel.;)
It will probably take about a week.

For Philip. It is not serious damage. It was only a light scratch really. No parts fell off, apart from some shaved aluminium and the area of the fuselage is unpressurised so not structurally critical. If no-one told them about it, it would of happily flown to the states and been discovered there. Saving about 100,000 litres of fuel. However, you don't know this until you look, on the ground.:D

Maybe they could have scrambled an F/A 18 with a ground engineer on board to inspect the damage....................Lucky engineer I say.:)

explains why a United 744 was sitting in the jetbase near the roundabout.

Not sure if this is relevant but I thought I'd point out that UA has a metallic strip of some sort that runs along the base of the fuselage on a number of aircraft types in their fleet. Is this some sort of protection against tailstrikes because I think they would have otherwised painted the area in blue. Also noticed this type of strip on other carriers

The strip you speak of is just an unpainted area of the fuselage. It is part of their colour scheme. I suspect it comes from the early 70's when most airlines had the bare aluminium along the bottom of the fuselage from front to rear. It was an easy way of preventing the paint scheme being damaged from the 47 various fluids that inevitably leak from an aircraft. The hydraulic fluid acts as an excellent paint stripper.
So rather than a constant cycle of clean and paint all the time they just leave it alone and polish it every so often.:D

The skin on the United B744 near the APU appeared to be no thicker than expected.

And I'm sure the pilots would appreciate the company effectively saying "Look, we appreciate you're good pilots (or so you think), but realistically we expect you're going to have a tail strike or 3 during your career with us, so we've taken the liberty of having extra thick tail strike protection added to our aircraft so you don't feel so bad if you give it a thump on departure. Just try not to use it too much, we can't afford too many repairs"

More than minor
 

There was more than trivial tail shell deformation, which probably explains the loose seats mentioned in ACARS. Oddly the ATSB report omits any mention of that ACARS transmission. I wonder if that's part of what they reviewed.

Bottom line seems to be a gust of cross and slight tail wind at VR combined with de-rated thrust led to some left column correction just at the commencement of rotation which in turn caused a spoiler-triggered momentary loss of lift sufficient to leave the a/c with insufficient ground clearance when rotate angle over-pitched to 4 degrees nose up. UA has now modified pilot training on their 744s from 3 degrees to 2.5 degrees of rotation to match Boeing's recommendations.

Basically a flukey wind condition just at the critical commencement of rotation was the primary cause, so I doubt that the (flying) PIC would suffer any opprobrium.

Hi Philip,

Why do you not believe the ATSB when they say that the damage was minor?

All said, it is minor damage on a 747. That structure at the back end of the aircraft is not pressurised and is not really structural. Ultimately it is an aluminium cover for the APU.

If another departing aircraft had not mentioned it to ATC the aircraft would have flown to its destination without any problems and then the defect would be picked up during the maintenance check there. (I said this earlier, I just noticed)

The ACARS that you are referring to states that there are loose floor panels not seats. Not related to the tail strike me thinks. The pax, pilots and cabin crew would have been totally oblivious to the tail strike. For the amount of damage it would have been a millisecond touch, not audible over the engine noise.

What is interesting though is if you look at the pictures that Tony G took there is not a moderate aileron input as suggested by the ATSB report. It must have been before the photos were taken. I wonder if the ATSB was aware of the existence of the photos?:D