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 ? enter image description here

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

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    $\begingroup$ 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. $\endgroup$
    – Ralph J
    Jan 24 '21 at 3:09
  • $\begingroup$ Infact 288degK at 0 ft altitude is = 15degC = ISA, so intended dev from ISA seems to be zero for purpose of the example question. $\endgroup$
    – skipper44
    Jan 24 '21 at 4:34
  • $\begingroup$ I agree, you are mixing temperature scales (K and C) and hence your incorrect result. $\endgroup$ Jan 25 '21 at 1:55

Finaly i have found the answer the error is on all book that published the equation there is the true equation enter image description here

  • $\begingroup$ What is the source of the original screenshot (i.e. what published the wrong equation)? $\endgroup$
    – Ralph J
    Jan 25 '21 at 15:22
  • $\begingroup$ Yes the original equation is given in PANS OPS Doc 8168 Chapter 4 section 3.4 $\endgroup$
    – Namster
    Jan 25 '21 at 15:48

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