B727 first officer reported that multiple system failures resulted in a diversion.

Attributes
ACN	1719195
Time
Date	202001
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	B727-200
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Hydraulic Main System
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Engineer Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 36000 Flight Crew Type 10000
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Immediately after takeoff upon gear retraction GPWS sounded 'whoop whoop pull up terrain' followed by erroneous airspeed and altimeter indications on both #1 and #2 airspeed and altimeters. Also standby altimeter appeared to be unreliable; about 3;000 feet error. ATC advised mode C on transponder was also in error so stopped squawk on mode C.[we then] asked to divert to a nearby alternate. ATC provided needed vectors and separation. During final approach phase lost most of a hydraulic system but were able to extend landing gear normally.at 1;000 feet GPWS again gave warnings - 'too low - flaps' but we were properly configured and on glide slope. [We] made a routine landing [but] engine #1 and #3 thrust reverser failed to open.

Original NASA ASRS Text

Title: B727 First Officer reported that multiple system failures resulted in a diversion.

Narrative: Immediately after takeoff upon gear retraction GPWS sounded 'Whoop whoop pull up terrain' followed by erroneous airspeed and altimeter indications on both #1 and #2 airspeed and altimeters. Also standby altimeter appeared to be unreliable; about 3;000 feet error. ATC advised mode C on transponder was also in error so stopped squawk on Mode C.[We then] asked to divert to a nearby alternate. ATC provided needed vectors and separation. During final approach phase lost most of A hydraulic system but were able to extend landing gear normally.At 1;000 feet GPWS again gave warnings - 'Too low - Flaps' but we were properly configured and on glide slope. [We] made a routine landing [but] engine #1 and #3 thrust reverser failed to open.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.