Certification of an airborne digital flight manual for the Gulfstream IV

In February 1990, the Gulfstream IV (G-IV) received Federal Aviation Administration (FAA) certification of the first complete airborne, digital FAA-approved airplane flight manual (AFM). The full AFM takeoff and landing computations are provided by the Honeywell PZ-800 performance/autothrottle computer. The computations extend far beyond Quick Reference Handbook (QRH) estimates found on the most advanced air transport aircraft. The PZ-800 predictions include the following for both full-rated and reduced-thrust takeoffs: `V speeds´ (decision (refusal) speed, rotation speed, safety (second-segment) speed, final segment speed, single-engine speed, and landing flaps reference speed) and distances (accelerate-stop, accelerate-go, and required field length). Landing computations also include speeds, distances and engine-settings. This system represents the first airborne application of a full digital flight manual. Approval of the PZ-800 takeoff and landing functions faced several certification and technical challenges. These challenges, as well as operation, design features, and testing of the PZ-800, are discussed