# Calculation of temperature correction for altimeter

I try to calculate the correction of cold temperature for altimeter , i use for this the equation 24 of the Engineering Sciences Data Unit (ESDU) publication but it give me very high number . if i take for example the given conditions altitude of aircraft 1000 ft 0 ft for aerodrome altitude t0 288 K temperature deviation from the ISA = 259.9812 L0 = 0.001981 the result is 599777.4389 ft is too big , the expected result is 60 ft So where is mistakes ?

EDIT : So i corrected the ISA dev according to what Ralph said but the result still incorrect i joint the step of calculation : the expected result is 60 ft

• 259 degree temp dev from ISA is unreasonable by an order of magnitude. You may be mixing C and K units there. Please fix that & edit your question accordingly.
– Ralph J
Commented Jan 24, 2021 at 3:09
• Infact 288degK at 0 ft altitude is = 15degC = ISA, so intended dev from ISA seems to be zero for purpose of the example question. Commented Jan 24, 2021 at 4:34
• I agree, you are mixing temperature scales (K and C) and hence your incorrect result. Commented Jan 25, 2021 at 1:55
• T aerodrome = 273K, T isa = 288K. so dT = 15K. Applying the correct formula (see Namsters' answer below) gives 15/0.001981 * ln (1+ 1.981/288) = 51.90ft (since dH aerodrome = 0). The table from PANS OPS Doc 8168 uses an approximation which works for temps above -15C (4 times the alt above the aerodrome in thousands of feet, times dT which equals 60). Commented Jul 21, 2022 at 15:22