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Service Bulletin 237

March Special  Flat Rate $49,900 (Short Mod.)

AD 2009-25-02 Effective date Jan 8, 2010. Compliance within 150 hrs. or 12 months.

Airworthiness Directive (AD) 2009-25-02 is now published and in effect concerning the Twin Commander Service Bulletin 237. It is required that all operators of the Twin Commander models 690, 690A, and 690B have an inspection performed to check for corrosion in the area between the surface of the left-hand/right-hand upper wing skins and the engine mount beam support straps. This inspection is required to be completed within the next 150 hours time in service or within the next 12 months.

We recommend scheduling your inspection early to avoid delays should there be any parts availability issues due to sudden demand for these repair kits. Because we had been a Twin Commander Service center for several decades and we have completed many of these inspections we have the expertise and experience to perform your inspection as thoroughly and timely as possible. We have a trained and experienced sheet-metal technician on staff and we have recently completed two of these inspections and modifications.

If you have any questions or concerns please don't hesitate to contact  our Maintenance Director Dan Gray at (207) 774-6318 ext. 150 or send him an email at DanGray@NortheastAir.com.

TWIN COMMANDER SB 237. ENGINE STRAP REPLACEMENT


The gear and engines are removed and the plane placed in a cradle and wings and engine supported. We use a curing agent on the support base so any movement can be detected. This is a good time to have your five-year gear inspection, spar replacement, –10 conversation or any avionics installation done to maximize your down time.

This is all so the opportune time to have SB 217. Engine Firewall Reinforcement accomplished.


The new skins are cut, fitted and match drilled for a precise fit



The skin and steel straps are riveted down in a wet bed of Proseal for added protection.



The top nacelle and support structure are removed. In this case, the short kit is being installed.


“Due to the complexity of the work and potential damage to the existing wing structure during performance of the modification section of the Service Bulletin, it is mandatory at least one member of the team accomplishing this task complete Twin Commander Aircraft approved training. Such training is available at Flight Safety International” Per SB 237 page 5.


The new improved steel straps have enhanced corrosion protection. Compliance with this modification is terminating action for the SB.


The skin and steel straps are riveted down in a wet bed of Proseal for added protection.


The effected area is masked off and painted to match.



Estimate

Northeast Air is using the suggested man-hours in the Service Bulletin for the flat rate price. We can turn the plane in four (4) to five (5) weeks depending on the work scope the customer requests. Please contact our Maintenance Director Dan Gray for a proposal. (207) 774-6318 ext. 150 or send him an email at DanGray@NortheastAir.com


Here is the damage found on this aircraft. It is a late model 690B-II. The lower spar cap was previously replaced and has been maintained by Twin Commander Service Centers.