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Malcolm

AC850 AND 851 DELAY DUE DENTS

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Last week family members (full revenue tickets) flew to LHR on AC, prior to departure YYC the aircraft was delayed due to the need to measure some dents from a birdstrike on the inbound flight. All was deemed to be well and off they went with only a 1+hour delay. They reported good service enroute.

Today leaving LHR the aircraft was again delayed to measure dents, this time caused by an over aggressive docking of the gate with the aircraft. This time there was a delay of over 3hrs.  Ah for the good old days of speed tape. :D  I imagine unless things have changed, my family members will again confirm good inflight service.  

AC staff at both YYC and LHR kept the passengers updated with the status of their flights. Again typical good AC service.

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Were they flying on a 787 for the return flight? With the carbon fibre fuselage, assessment of fuselage dents is a little more complicated than the good old days of aluminum. 

Edited by J.O.
Making it make sense

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8 minutes ago, J.O. said:

Were they flying on a 787 for the return flight? With the carbon assessment fuselage, assessment of fuselage dents is a little more complicated than the good old days of aluminum. 

Both were shown as 777-300 .   However no complaints re erring on the side of caution and getting the dents assessed. Perhaps the extra time was needed due to the location of the Damage in LHR (only the AME's know what lurks close under the Aluminum Skin :D )

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Leading edge dents? If so, features of same including number, location, depth, and width, etc., must be considered carefully by mtx personnel; hard limitations do apply.

Wind tunnel experiments demonstrate the nasty flow patterns that are generated aft of LE deformations at varying angles of attack. Even variations of as little as .002 " in the profile of the LE can result in the complete loss of lift over the affected portion of the wing's chord.

Edited by DEFCON
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Determination of whether  a dent is "go / no-go" can be tricky, depending on the location on the fuselage, and of course it's done in accordance with the Structural Repair Manual. Since this damage was caused by impact with the bridge, then it's possible the dents are in the vicinity of the pitot-static ports, where tolerances are tighter. 

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Inventive, but the patch is likely home grown and inappropriate for obvious reasons.

 

 

 

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But is the procedure found in the 'approved' mtx manual, or is it a homegrown battlefield patch?

Snag deferrals in a log don't necessarily guarantee the repair meets an 'approved' standard, mtx personnel can be creative people. The product on the le shown may be aluminum tape, which as far as I can recall isn't approved for use above speeds that are quite low, but if the product is some kind of common fiberglass reinforced speed tape, I'd bet on the fix being homemade. Regardless, either way, your picture tells an aerodynamic story.

 

 

.

  

Edited by DEFCON

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3 minutes ago, DEFCON said:

isn't approved for use above speeds that are quite low

Then why is it called Speed Tape?

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People that drive sporty cars probably named it? I've heard it referred to as 100 mph tape too.

 

 

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Rich; seriously, Mx needs to re-visit this "temporary repair". When this tape is first applied, there is always a "monitor" associated with it, stating that it will be re-inspected for condition periodically (every 48 hours?). Someone needs to start doing their job, which encompasses maintaining the airworthiness of the ship.

Edited by conehead
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51 minutes ago, conehead said:

Rich; seriously, Mx needs to re-visit this "temporary repair". When this tape is first applied, there is always a "monitor" associated with it, stating that it will be re-inspected for condition periodically (every 48 hours?). Someone needs to start doing their job, which encompasses maintaining the airworthiness of the ship.

Agreed, that's about a 5 minute job to put fresh tape on there. It's not really a hazard but it is certainly not something a professional would leave as is.

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Can anyone produce a reference from the maintenance manual of any swept wing aircraft that approves the use of tape to remedy a leading edge dent defect?

 

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1 hour ago, DEFCON said:

Can anyone produce a reference from the maintenance manual of any swept wing aircraft that approves the use of tape to remedy a leading edge dent defect?

 

It's often used for an area that requires aerodynamic sealant but there isn't sufficient time to allow it to set up. I don't think this is the case here and I'm actually kind of mystified as to why it would be there.

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Yes, 'approved aluminum tape' is allowed as an aerodynamic sealant on some types, in limited locations, but as far as I know, never duct tape.

When duct tape is applied it stretches and conforms to the shape of the dent, which only makes the aerodynamic degradation worse, Rich's picture demonstrates the point.

 

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4 hours ago, Rich Pulman said:

speed tape begins to shred at 450 knots (IAS).

450 Knots indicated?  What kind of aircraft do you fly that you see 450 KIAS? 

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2 minutes ago, Rich Pulman said:

Yes, 450 indicated. That was in a T-33 which could reach 505 KIAS.

Ahh, that makes sense.  Wasn't thinking about military aircraft.

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On 2017-07-18 at 8:51 AM, conehead said:

Rich; seriously, Mx needs to re-visit this "temporary repair". When this tape is first applied, there is always a "monitor" associated with it, stating that it will be re-inspected for condition periodically (every 48 hours?). Someone needs to start doing their job, which encompasses maintaining the airworthiness of the ship.

Standard procedure at AC, may not be at other operators like the one in the picture. 

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On 2017-07-18 at 0:08 PM, DEFCON said:

Can anyone produce a reference from the maintenance manual of any swept wing aircraft that approves the use of tape to remedy a leading edge dent defect?

 

May not be in the specific maintenance manual for that aircraft type but is an approved repair in the SRM for the aircraft. With inspection intervals and permanent repair terminating action limit. 

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On 2017-07-16 at 11:45 PM, Rich Pulman said:

Do they have to measure the wrinkles in the speed tape covering the dents?

IMG_4012.JPG

Looks like speed tape that has been left in place too long. Speed tape is in the SRM. 

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Gentlemen

Having been out of the industry for awhile now, I thought it would be a good idea to do some research before commenting further. I searched high, low and everywhere in between, including discussions with the most qualified aerodynamics and structural experts in this Country to find any evidence that would support the use of 'speed tape' to smooth, or beautify dents in the leading edges of supercritical swept wings.

Although we didn't examine the manuals of every air carrier aircraft type flying, everyone agreed in principle and so, my challenge to anyone with an opinion on the matter stands; can anyone produce a reference from 'any' relative aircraft manual, CDI, SRM, or AMM for instance that supports the use of speed tape to smooth dents in the leading edges of supercritical swept wings.

 

Edited by DEFCON

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There are 2 kinds of "Speed Tape"  There is the relatively thin stuff that is used to cover areas of disbond or missing sealant and then there is the "good Stuff" that is significantly thicker and stronger.  The latter can be used in many areas of the aircraft however there is none that I am aware of that are approved for use on the aircraft leading edge.  Speed tape is approved for use on Winglets however on some models.

 

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