COLOGNE, Germany – Bruised by a failed program that ate through $700 million five years ago, defense officials here are eager to avoid painful mistakes as they prepare the purchase of three Northrop Grumman-made “Triton” unmanned aircraft from the U.S. Navy.

Especially when it comes to the new drones’ airworthiness in shared airspace, Berlin wants to make sure there are program off-ramps predefined in case the aircraft fail to get the necessary permits, the government has told lawmakers.

For example, officials want a section in the contract dedicated to an “airworthiness qualification plan,” states a defense ministry response to members of the leftist Die Linke party, first reported by the Tagesschau website.

In addition, Germany wants to be able to walk away if certification of the Triton’s sense-and-avoid system by U.S. authorities fails to translate into approval by the Bundeswehr’s own safety inspectors.

The acquisition of the U.S. Navy’s derivative of the Global Hawk is called “Pegasus” in Germany, which is short for “Persistent German Airborne Surveillance System.” Berlin recently received word from Washington that a foreign military sales case would be granted in response to Germany’s request for the aircraft.

Contract negotiations are expected to conclude in the first half of 2019. The first Pegasus drone will reach the Bundeswehr inventory in 2025.

The “Euro Hawk, ” canceled in 2013, was a textbook example of seemingly trivial acquisition oversights that end up sinking a program. Designed to carry the awkwardly named “ISIS” signals-intelligence sensor, made by an Airbus subsidiary, regulators never certified the Euro Hawk to fly safely in the skies above Europe.

The program almost sacked the German defense minister at the time, who was criticized for failing to flag the airworthiness-certification problem early enough in the program.

Mimicking a human’s course of action to avert an impending mid-air collision remains a difficult problem in drone aviation. German officials have justified the Triton purchases, worth more than $2 billion, by arguing the U.S. work on flight-safety issues was more advanced than German efforts, and that the U.S. Navy’s certifications to that effect would be more or less applicable in Europe.