Reduced Vertical Separation Minimum Reduced Vertical Separation Minimum (RVSM)(RVSM)

RVSM RVSM Skin Waviness Inspection Skin Waviness Inspection

Procedures Procedures

For Cessna Model 500/501 and For Cessna Model 500/501 and 550/551 Citation Aircraft550/551 Citation Aircraft

Equipment NeededEquipment NeededThe equipment needed to The equipment needed to complete the task complete the task include:include:Skin Waviness Inspection Skin Waviness Inspection Procedures Document Number Procedures Document Number R34-0206R34-0206Skin Map Reference Bar – Skin Map Reference Bar – With Base (part # KSR TOL With Base (part # KSR TOL 723)723)Dial Indicator Depth Gauge Dial Indicator Depth Gauge (part # Mitutoyo 547-217)(part # Mitutoyo 547-217)24 in. Flexible Steel Ruler 24 in. Flexible Steel Ruler (various)(various)Grease Pencil or Dry Erase Grease Pencil or Dry Erase Marker (variousMarker (various))

Establishing a Reference GridEstablishing a Reference Grid

Draw a vertical line Draw a vertical line through the upper and through the upper and lower static ports at least lower static ports at least 6 inches above and 6 inches above and belowbelow

Locate a point midway Locate a point midway between the upper and between the upper and lower static ports and lower static ports and markmark

Determine the distance from Determine the distance from the center point of the static the center point of the static ports to the skin overlay below ports to the skin overlay below the static ports (approximately the static ports (approximately 3.25 in) 3.25 in) At a point about 12 inches At a point about 12 inches forward of the static ports, forward of the static ports, measure up from the skin measure up from the skin overlay this same offset and overlay this same offset and mark (approximately 3.25 in)mark (approximately 3.25 in)

Using the 24 inch straight edge Using the 24 inch straight edge and dry erase marker, draw a and dry erase marker, draw a horizontal line through the horizontal line through the centerline of the static ports centerline of the static ports and the mark made from the and the mark made from the previous step being sure the previous step being sure the extend the line at least 14 in. extend the line at least 14 in. forward of the static port center forward of the static port center line and at least 4 in. aft.line and at least 4 in. aft.

Verify that the horizontal Verify that the horizontal line is parallel with the line is parallel with the skin overlay below and skin overlay below and that the line extends at that the line extends at least 14 inches forward of least 14 inches forward of the ports and at least 4 the ports and at least 4 inches aft as showninches aft as shown

Locate the double vertical Locate the double vertical row of rivets approx. 3 row of rivets approx. 3 inches aft of the static inches aft of the static portsports

Locate a point just Locate a point just forward of these rivets, forward of these rivets, centered between these centered between these and the rivet just forwardand the rivet just forward

Measure the distance of Measure the distance of this point from the vertical this point from the vertical line drawn in step 1 and line drawn in step 1 and record for next steprecord for next step

Measure aft from the top Measure aft from the top and bottom of the vertical and bottom of the vertical line the same distance line the same distance and markand mark

Using the 24 inch straight Using the 24 inch straight edge and the dry erase edge and the dry erase marker, draw a vertical marker, draw a vertical line through these points line through these points as shown in middle photoas shown in middle photo

When finished, your line When finished, your line should resemble the one should resemble the one shown in lower photoshown in lower photo

At a point 15 inches At a point 15 inches forward of the aft vertical forward of the aft vertical line just drawn, use the line just drawn, use the straight edge and dry straight edge and dry erase marker to draw a erase marker to draw a vertical reference linevertical reference line

This vertical reference This vertical reference line should extend 8 line should extend 8 inches above and below inches above and below the horizontal reference the horizontal reference line line

The grid should now look The grid should now look like the top photolike the top photo

Next, for both vertical Next, for both vertical reference lines (fore and reference lines (fore and aft lines), mark each 1 aft lines), mark each 1 inch increment (up to 7 inch increment (up to 7 inches above and below inches above and below the horizontal reference the horizontal reference line) line)

Both vertical reference lines Both vertical reference lines should now be incremented as should now be incremented as shown in top photoshown in top photo

Next step is to number the Next step is to number the incrementsincrements

Positive numbers above the Positive numbers above the horizontal reference line and horizontal reference line and negative numbers below the negative numbers below the line as shown in lower photoline as shown in lower photo

Verify the vertical lines are Verify the vertical lines are parallel by measuring the parallel by measuring the distance between the lines at distance between the lines at the positive and negative the positive and negative seven inch mark (both should seven inch mark (both should measure 15 inches) before measure 15 inches) before continuingcontinuing

Depth Gauge SetupDepth Gauge Setup

Start by adding the 2.5 Start by adding the 2.5 inch extension and inch extension and reinstalling the plunger reinstalling the plunger

end into the gaugeend into the gauge, , ensure that the tip is ensure that the tip is secured into placesecured into place

Place the reference bar Place the reference bar on a flat smooth surface on a flat smooth surface and place the depth and place the depth gauge in the reference gauge in the reference bar trackbar track

Place the gauge near one Place the gauge near one end of the reference barend of the reference barZero the dial by pressing Zero the dial by pressing ZERO/ABS, the gauge ZERO/ABS, the gauge should read 0.000should read 0.000Confirm this zero Confirm this zero (+(+/- 0.002) /- 0.002) at the opposite end of the at the opposite end of the reference barreference barNow check the function of Now check the function of the dial depth gauge. Ensure the dial depth gauge. Ensure the gauge reads negative the gauge reads negative numbers when plunger is numbers when plunger is extended and positive when extended and positive when retractedretracted(If not, press +/- button on gauge and (If not, press +/- button on gauge and confirm proper sign, This should be confirm proper sign, This should be reconfirmed periodically during the reconfirmed periodically during the measurement process)measurement process)

Skin Map MeasurementSkin Map Measurement

Begin by aligning the Begin by aligning the reference bar with the +5 reference bar with the +5 inch mark on the vertical inch mark on the vertical reference linesreference lines

While firmly holding the While firmly holding the reference bar in place, reference bar in place, stick the depth gauge stick the depth gauge through the space in the through the space in the bar and align the gauge bar and align the gauge at the 1 inch increment at the 1 inch increment

Ensuring the depth gauge Ensuring the depth gauge is seated, now record the is seated, now record the measurement in table A1 measurement in table A1

Proceed to the 2 inch Proceed to the 2 inch increment on the bar and increment on the bar and record the measurementrecord the measurement

Continue until all 13 Continue until all 13 increments are recorded increments are recorded from barfrom bar

Now move reference bar Now move reference bar down to remaining vertical down to remaining vertical reference lines and record reference lines and record measurements in table A1measurements in table A1

Additional Recording MethodsAdditional Recording MethodsMeasurements can also Measurements can also be recorded by using a be recorded by using a Windows based computer Windows based computer equipped with MS Excel equipped with MS Excel

Plug the supplied depth Plug the supplied depth gauge cable assembly gauge cable assembly shown in photos into a shown in photos into a USB port of the computerUSB port of the computer

Open the MS Excel Open the MS Excel spreadsheet for RVSM spreadsheet for RVSM Waviness RecordingWaviness Recording

Additional Recording Methods Additional Recording Methods (cont.)(cont.)

With the computer, select With the computer, select the corresponding the corresponding spreadsheet cell for the spreadsheet cell for the grid point to be recordedgrid point to be recordedOnce the depth gauge is Once the depth gauge is firmly in place press the firmly in place press the DATA button on the DATA button on the depth gauge accessory depth gauge accessory as shown in photoas shown in photoVerify measurement was Verify measurement was recorded in correct cellrecorded in correct cellRepeat procedures for Repeat procedures for the rest of the grid pointsthe rest of the grid points

Slope CalculationSlope Calculation

Start at Horizontal Grid reference 5.0 and Reference Bar Start at Horizontal Grid reference 5.0 and Reference Bar Graduation 12.0, note the recorded measurementGraduation 12.0, note the recorded measurementSubtract this record measurement from the recorded Subtract this record measurement from the recorded measurement to the left, in his case, Horizontal Grid measurement to the left, in his case, Horizontal Grid Reference 5.0 and Reference Bar Graduation 13.0Reference 5.0 and Reference Bar Graduation 13.0Enter the result in corresponding location in Table A2, in Enter the result in corresponding location in Table A2, in this case, Horizontal Grid Reference 5.0 and Reference this case, Horizontal Grid Reference 5.0 and Reference Bar Graduation 12.0Bar Graduation 12.0Repeat steps 1-3 for the remaining Reference Bar Repeat steps 1-3 for the remaining Reference Bar GraduationsGraduationsRepeat steps 1-4 for the remaining Horizontal Grid Repeat steps 1-4 for the remaining Horizontal Grid Reference rows downReference rows down

Skin Overlay MeasurementsSkin Overlay Measurements

Ensure the skin waviness Ensure the skin waviness procedures are completedprocedures are completed

Begin by using the 24 inch Begin by using the 24 inch ruler to mark (12) one inch ruler to mark (12) one inch increments starting at the increments starting at the aft vertical reference line aft vertical reference line and going forward along and going forward along the aircraft skin overlaythe aircraft skin overlay

When complete the When complete the aircraft should resemble aircraft should resemble the lower photo the lower photo

Remove the 2.5 inch Remove the 2.5 inch plunger extension from plunger extension from the gauge and reinstall the gauge and reinstall the tip, make sure the tip the tip, make sure the tip is properly tightened to is properly tightened to the depth gaugethe depth gaugeVerify that the plunger is Verify that the plunger is able to retract flush with able to retract flush with the blue base plate of the the blue base plate of the depth gauge depth gauge If plunger fails to retract If plunger fails to retract fully into base plate as fully into base plate as shown in lower photo, shown in lower photo, please perform base please perform base plate adjustments in next plate adjustments in next step step

Depth Gauge Base Plate Depth Gauge Base Plate AdjustmentAdjustment

Using the supplied hex Using the supplied hex key, loosen the set screw key, loosen the set screw in the base plate and in the base plate and adjust the depth until the adjust the depth until the plunger is able to fully plunger is able to fully retract into the gauge retract into the gauge base platebase plate

Secure base plate by Secure base plate by retightening the set screw retightening the set screw and continue with skin and continue with skin overlay procedures overlay procedures

Skin Overlay ProceduresSkin Overlay ProceduresPosition the gauge near the Position the gauge near the skin overlay mark such that skin overlay mark such that the plunger is depressed by the plunger is depressed by the upper fuselage skinthe upper fuselage skinWhile holding the gauge in While holding the gauge in place, zero the gauge by place, zero the gauge by pressing the ZERO/ABS pressing the ZERO/ABS button button Now place the gauge base Now place the gauge base plate on the upper fuselage plate on the upper fuselage skin with the plunger next to skin with the plunger next to the skin overlay as shown in the skin overlay as shown in lower photo (also see figure lower photo (also see figure 5.2)5.2)

Start at the aft skin Start at the aft skin overlay index mark (1 overlay index mark (1 inch forward of aft vertical inch forward of aft vertical reference line as shown reference line as shown in top photo) in top photo)

Record measurement Record measurement (gap between upper and (gap between upper and lower fuselage skin) onto lower fuselage skin) onto Figure A.1, Figure A.1,

Now proceed to next Now proceed to next overlay index mark and overlay index mark and repeat until all 12 index repeat until all 12 index marks are measured and marks are measured and recordedrecorded