TM 1-1500-204-23-4 Table 4-2.  Scale Error (Three Pointer) Equivalent atmospheric pressure (mercury) Altitude Tolerance test ( feet) pressure at (feet) (mm) (inches) ± 25°C 0 760.00 29.921 30 500 746.37 29.385 35 1,000 732.93 28.856 35 1,500 719.70 28.335 40 2,000 706.65 27.821 40 2,500 693.80 27.315 45 3,000 681.14 26.817 45 4,000 656.38 25.842 50 5,000 632.36 24.896 55 6,000 609.05 23.978 60 8,000 564.51 22.224 70 10,000 522.65 20.577 80 12,000 483.34 19.029 90 14,000 446.46 17.577 100 15,000 428.90 16.886 105 16,000 411.90 16.216 110 18,000 379.53 14.942 120 20,000 349.25 13.750 130 22,000 320.96 12.636 140 25,000 282.03 11.103 155 30,000 225.69 8.885 180 Table 4-3.  Test Tolerances (Three Pointer) Tolerance Test (feet) Case leak test ............................................ ±100 Hysteresis test: First test point (16,000) 75 Second test point (12,000) 75 After-effect test .............................................. 30 Table 4-4.  Friction Test Tolerances (Three Pointer) Altitude Tolerance (feet) (feet) 1,000........................................... ±70 2,000........................................... 70 3,000........................................... 70 5,000........................................... 70 10,000........................................... 80 15,000........................................... 90 20,000........................................... 100 25,000........................................... 120 30,000........................................... 140 Change  3   4-17