AD 73-20-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Transcontinental and Western Air, Inc. | Army B-17F | BOEING Model B-17F & G Airplanes |
| aircraft | Transcontinental and Western Air, Inc. | Army B-17G | BOEING Model B-17F & G Airplanes |
Unsafe Condition
Cracking in the front spar lower cap center section, part number 753424-2, around the bolt hole in both the forward and aft wall of the tube, particularly at the top and bottom portions.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove the most inboard bolt from the 8 bolt pattern, inspect using eddy current or borescope with dye penetrants for cracks. Replace or repair if cracks found, install access panels as needed, and reinspect at intervals not exceeding 50 hours' time-in-service or 12 months. For reamed holes, reinspect within 1500 flight hours and revert to 150-hour interval thereafter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 25 hours' time-in-service or within 6 months after the effective date of this AD, unless already accomplished within the last 25 hours' time-in-service or 6 months.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
BOEING Model B-17F & G airplanes certificated in all categories.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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