Learjet Fall 2006

• Learjet Lower Cabin Door Cracking
• Airfone Service to be Discontinued
• So You Want to File for a “Mode S” Exemption?

Learjet Lower Cabin Door Cracking

— Dave Schiver

There has been an on-going issue with the Learjet 20 & 30 Series lower cabin doors having cracks in the forward or aft frames. These are usually at the top of the frame closest to the hinge on the forward frames. But Duncan Aviation technicians have also seen the aft crack frequently. These cracks are typically underneath the sealer that has built up in the corners of the door. To see the entire crack, this sealer must be removed. The end will usually be underneath an angle or doubler. There is a misconception that AAK 81-2 (24” doors) or AAK 89-16 (36” doors) is a repair for these cracks. These are not repairs but reinforcements to the existing frames. The actual repair for these cracks is to replace the cracked frame. To accomplish this, the old frame rivets are drilled out through the door skin and the new frame is riveted on. Keep in mind that when replacing a door frame all aircraft equipment must be completely installed. Door frame replacement should only be done when both engines and interior have been installed and the wings and tips filled with fuel, if applicable. While the repair is in progress all other personnel should be kept out of the aircraft.

This issue arises when an aircraft comes in for paint and the door frames are not inspected. Then during the next inspection if the door frames are found cracked, the new paint must be disturbed.We suggest having all door frames inspected before any paint work. If the door frame is replaced, two days will be added on the front end. After every door frame replacement, always add AAK 81-2 or AAK 89-16, as applicable to reinforce the door frames. Please keep in mind that if a door frame is being replaced without paint work that there will be more downtime to paint the door with stripes.

Airfone Service to be Discontinued

Verizon Airfone recently announced that it would discontinue air-to-ground phone service on Dec. 31, 2007. Verizon is encouraging customers to “seek an alternative hardware and service provider who specializes in airborne telecommunications.” Approximately 4,000 aircraft are currently equipped with the MagnaStar system, which will be affected. Duncan Aviation has developed several telecommunication solutions for operators who are faced with this looming disruption of phone service. For more information about options available, contact Steve Elofson in Lincoln at 800.228.4277 ext. 1603 or Kim Konopnicki in Battle Creek at 800.525.2376 ext. 8417.

So You Want to File for a “Mode S” Exemption?

Are you planning to travel to Europe without a Mode S Exemption? If you wish to declare compliance with Mode S Enhanced Surveillance (EHS) or apply for exemption, you may use a downloaded Excel-based form found online at:

• www.eurocontrol.int/msa/public/standard_page/
  modes_trans_arrange_coord_cell.php

The following Excel-based forms available are as follows:

1. Aircraft Not Mode S Enhanced Surveillance Capable
2. Delayed Installation
3. Taken Out of Service
4. Test, Delivery, or Maintenance Flights or Occasional Access Flights

Also found on the Exemption Coordination Cell (ECC) webpage are various means to return the completed forms.

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