The A320 involved (D-AIPX, MSN147, ff 29.11.1990) was close to the Airbus quoted Flight Hours (FH) and Flight Cycles (FC) as intended Design Service Goal (DSG) according to another contributor (FH 58,300 hours, 46,700 FC, Airbus DSG 60,000 hours, 48,000 FC). As far as I understand the extension to service life has/had two phases. Phase I (Interim Service Goal, ISG, tradeoff of FH and FC) requiring an inspection and Phase II (ESG I) requiring airframe modifications. Had D-AIPX undergone both ESG (Extended Service Goal) phases? What kind of modifications are required for ESG I?
D-AIPX had just reached FL380 close to its certified max service ceiling, when things started to go wrong.