PART 4 - ULTRASONIC

WING LEADING EDGE KRUEGER FLAPS NO. 11 AND 16

1. Purpose

A. Use this procedure to do an inspection for damage on the outboard Krueger flaps.

B. After the service bulletin has been done, use this procedure again to examine the changed area of the

outboard Krueger flaps for disbonds and delaminations.

C. The location of the No. 11 Krueger flap is on the left side of the airplane, inboard of the engine strut.

The No. 16 Krueger flap is at the same location on the right side of the airplane. See Figure 1, sheet 1.

D. The Krueger flaps will be removed from the airplane to do this inspection and to do the service bulletin

changes.

E. Service Bulletin Reference: 747-57-2299, 747-57-2328

2. Equipment

A. General

(1) This procedure gives instructions for two through-transmission inspection modes:

(a) Water-jet coupled Manual Through-Transmission Ultrasonics (MTTU).

(b) Dry-coupled Wheel-Transducer Through-Transmission Ultrasonics (WTTU).

(2) If you have access to a computer-aided TTU (CATTU) system, we recommend that you use it for

this inspection. Refer to Part 4, 51-00-02, for data about CATTU scan equipment.

(3) We do not recommend the use of hand-held contact TTU (CTTU) for this procedure.

(4) Refer to Part 1, 51-01-00 for data about the equipment manufacturers.

B. Instrument

(1) All ultrasonic instruments are permitted if they can do the calibrations specified in this procedure.

The ultrasonic instruments specified below were used to prepare this procedure:

(a) USL 48, made by Krautkramer Branson

(b) Sonic 136, made by Staveley Instruments (with preamplifier)

(d) USM3S, made by Krautkramer Branson

(2) For ATTU inspection, refer to Part 4, 51-00-06.

C. Transducers

(1) We recommend 1 MHz transducers to do this inspection. It is satisfactory to use other

frequencies if you can do the calibrations specified in this procedure. The transducers specified

below were used to prepare this procedure:

(a) 0.50 inch (13 mm) transducers -- Part number JA4-1.0/.5 (1 MHz); made by NDT

Engineering Corp. (for MTTU).

(b) 0.375 inch (10 mm) x 0.50 inch (13 mm) transducers -- Part number DCR-581 (1 MHz);

made by NDT Engineering Corp. (for WTTU).

(2) For ATTU inspection, refer to Part 4, 51-00-06.

747

NONDESTRUCTIVE TEST MANUAL

PART 4 57-50-01

Page 1

Nov 15/2015D6-7170

EFFECTIVITY

ALL; 747 AIRPLANES WITH COMPOSITE KRUEGER

FLAPS

Boeing 747 - Page 77

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