# AD 52-28-05: Center Wing Lower Access Hole

- Type: Airworthiness directive
- Status: Current
- Products: Boeing DC-6, DC-6A and DC-6B
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Registered aircraft: 17 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/53B3F79A9ED3CFD1862569BC00620F49.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/52-28-05

## The airworthiness directive

52-28-05 DOUGLAS: Applies to All Model DC-6 Series Aircraft (Fuselage Numbers 1 to 213 Inclusive).

Compliance required as indicated.

The following inspections and rework pertain to the center wing lower surface access hole structure at Station 149.

1. Inspection.

  (a) Conduct following inspection as soon as practical but not later than the next 50 hours operation unless already accomplished and continuing thereafter at regular periodic inspection intervals nearest to 500 hours from the time of initial inspection until permanent repair is made as outlines in 2(b). Using at least an 8-power magnifying glass and/or dye check method or equivalent, make inspections for cracks in the lower wing skin and doubler at the aft access hole paying particular attention to the corner areas. Alternate inspection procedures which will provide equivalent safety may be approved. If cracks are found, make repairs as indicated in item 2 before the next schedules flight.

  (b)Periodic visual inspection must be continued at the most frequently established inspection period between 15 and 35 flying hours for airplanes reworked, as per item 2(a) until the rework of item 2(b) is accomplished. If a crack is found beyond the stop drill hole prior to the replacement period as indicated in item 2(c) make repair as per item 2(b) before the next scheduled flight.

2. Repair.

  (a) If cracks are found in either the lower wing skin or doubler less than 1-inch long, stop drill using a 1/4-inch drill or 3/8-inch drill hole if space permits. The combined length of the crack and drill hole should not exceed 1 1/4 inches in total length.

  (b) If cracks are found in either the lower wing skin or doubler greater than 1-inch long, or if the cracks extend under the adjacent angle which cannot be visually inspected, incorporate the rework on Douglas Drawing No. 5400661 before the next scheduled flight. In cases where only one corner of the access hole is cracked, Douglas approved interim repair may be used subject to replacement with permanent rework, per Drawing No. 5400661, within a period not to exceed 1,500 hours from time interim repair is made.

  (c) The rework of item 2(a) must be replaced with the rework reinforcement of item 2(b) within 3,000 flying hours from time rework of item 2(a) is accomplished.

(Douglas Service Letter No. 130, dated July 10, 1952, also covers this same subject.)

## Affected data sheets (3) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS 6A3](https://openairdocs.org/tcds/6A3): The Boeing Company; names 1 of 3 models: DC-6A
- [TCDS 6A4](https://openairdocs.org/tcds/6A4): The Boeing Company; names 1 of 2 models: DC-6B
- [TCDS A-781](https://openairdocs.org/tcds/A-781): The Boeing Company; names 1 of 1 models: DC-6

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 17 (17 by airframe model, 0 by engine model)
- Makers: Douglas 17

Models with the most aircraft:

- [Douglas DC-6B](https://openairdocs.org/model/douglas-dc-6b): 9 aircraft (airframe model)
- [Douglas DC-6A](https://openairdocs.org/model/douglas-dc-6a): 7 aircraft (airframe model)
- [Douglas DC-6](https://openairdocs.org/model/douglas-dc-6): 1 aircraft (airframe model)

All 3 models: https://openairdocs.org/ad/52-28-05/models.md
Every aircraft: https://openairdocs.org/ad/52-28-05/aircraft.md

Its text cites no advisory circulars or STCs.

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