Roger H. Hoh - President – Hoh Aeronautics, Inc.

Academic Background

Bachelor of Science in Aerospace Engineering, California State Polytechnic University, 1964

Master of Science in Aerospace Engineering, University of Southern California, 1968

Professional Experience

Mr. Hoh has been involved with research, development, and evaluation of fixed and rotary wing aircraft performance, handling qualities, flight control systems, and cockpit displays since 1964, and is the primary author of over 60 published technical reports and papers related to these subjects.  He is the founder and president of Hoh Aeronautics, Inc. (HAI). (See website at “”).

Mr. Hoh’s current primary activity is FAA and EASA certifications of a low-cost lightweight stability augmentation system and autopilot (HeliSASTM) for light helicopters.   He developed the control laws and safety monitors for this system, was the project test pilot for all engineering development, and served as an FAA DER test pilot for certification flight-testing of some helicopter models.  STCs have been issued for installation of HeliSAS on the Robinson R44, Bell 206B and 206L1, L3, L4, Bell 407 and AS350B2 and B3, and EC130B4 helicopters. He holds a patent covering unique design features of the HeliSAS. 

Other current projects include the development of control laws for a head-up display for a new business jet to accomplish low visibility takeoffs (300 RVR) and landings (Cat IIIa).  He is also working with the National Test Pilot School to develop a flight syllabus and course for SAS/Autopilot training using a Bell 212 helicopter equipped with HeliSAS and integrated with the Chelton Flight Logic EFIS.

Mr. Hoh was the project engineer and primary developer of the military flying qualities specification ADS-33E-PRF and the supporting Background Information and Users Guide. More recently he developed a test guide for the U.S. Army Aeroflightdynamics Directorate at NASA Ames to provide background and guidance into flight test techniques and data interpretation as required to demonstrate compliance with the flying qualities specification for military rotorcraft (ADS-33E-PRF).

Past projects accomplished by Mr. Hoh are listed below, in inverse chronological order.

·         Present course on fly-by-wire flight control systems to major helicopter manufacturers and government test agencies.  This course was delivered with co-presenters from the U.S. Army Aeroflightdynamics Directorate at the NASA Ames Research Center.

·         Continue to provide technical support to a major U.S. airline for the BAE systems head-up display installed on 737-800 aircraft.

·         Accomplished study for FAA to develop criteria for rudder flight control systems for transport aircraft in up-and-away flight conditions.  Goal was to develop criteria to minimize the tendency for rudder overcontrol, which has proven to be catastrophic.  Phases 1 and 2 of this study were accomplished on the NASA Ames Vertical Motion Simulator, and Phase 3 is pending.

·         Support the Army/NASA Rotorcraft Division at NASA Ames on the development of a digital flight control system for the CH-47F.  This was an extension of earlier work to develop improved control laws for the CH-47E in cooperation with Boeing Helicopters.  He is also assisting the Army with a flight control system upgrade to the AH-64 Apache.

·         Assist US Army with development of control laws for AH-66 Comanche helicopter (now cancelled).

·         Developed the control laws and symbology, and was the project test pilot, on the BAE Systems head-up display (HUD) that is now certified for use on the Boeing 737-800 aircraft to accomplish manually flown Cat IIIa landings and 300 RVR takeoffs.  This work also included the development, execution, and reporting of FAA certification testing in the moving base simulator (1000 run Monte Carlo simulation) and aircraft.  The BAE HUD is in use on American Airlines and South African Airlines Boeing 737-800 aircraft.

·         Developed a PC-based pilot training program for the BAE Systems HUD, that is marketed as the Visual Guidance System (VGS).  This program is in use to train 737 pilots at major U.S. and foreign airlines.

·         Developed handling qualities criteria for helicopters with external loads for the U.S. Army.  This project included four simulation periods on the NASA Ames Vertical Motion simulator.

·         Performed analysis, simulation and variable-stability flight testing of concepts for limited authority attitude command flight control system for U.S. Army rotorcraft.

·         Developed the useable cue environment (UCE) methodology to quantify the tradeoff between increased stabilization and degraded visual cueing for helicopters when operating in degraded visual environments, such as when using night vision goggles (NVGs) or forward looking infrared (FLIR) vision aids.  This is an important element of the ADS-33E rotorcraft flying qualities specification.

·         Formulated and tested the concept of Bandwidth as a handling qualities criterion as well as numerous other helicopter handling qualities criteria and created the concept of Mission Task Elements and Response-Types that are used in ADS-33E and accepted as standard methodology worldwide.  Involved piloted moving base simulation and variable stability flight testing on the Canadian National Research Council Bell 205.

·         Assist with the development of criteria to predict and prevent pilot induced oscillations for the US Air Force. 

·         Test Director on a combined FAA, DOD, Industry program to test the results of displaying raster images from millimeter-wave and infrared sensors on a head-up display installed in a Gulfstream II business jet.  He also developed the control laws for the head-up display guidance, and performed as an evaluation pilot during the acceptance testing of two Millimeter Wave radars, and one FLIR.  The objective of that program was to create a database of sensor and pilot performance with “enhanced vision”. The demonstration system was used to conduct approaches in actual Cat IIIa weather conditions using Cat I ILS facilities across the United States.

·         Development and flight-testing of the control laws for two Head-Up Displays.  These systems have been certified by the FAA to allow manual Cat IIIa landings for the deHavilland Dash 8-300 and 400 and the Boeing 737-300 and 400. 

·         Assist with the development of flight control systems for three aircraft manufacturers.  These include a fly-by-wire transport, a turboprop commuter, and an executive jet. 

·         Assist a transport aircraft manufacturer with the analysis, simulation, and variable stability flight testing of a fly-by-wire flight control system for a very large fixed-wing transport aircraft

·         Investigation of decelerating approaches to city center heliports in IMC conditions for the FAA.  Flight test evaluations were performed on the Canadian NRC variable stability Bell 205.

·         Mr. Hoh has been the Project Engineer on government sponsored studies to incorporate major modifications into all three military handling qualities specifications:  1) Conventional Aircraft (MIL Standard 1797A to replace MIL‑F‑8785C), 2) VSTOL aircraft (MIL‑F‑83300), and 3) helicopters (MIL‑H‑8501A).  The major thrust of these upgrades has been to effectively account for modern, multiply redundant, high gain, high authority flight control systems in the revised specifications.

·         Analysis and flight testing of direct-force control modes for fighter aircraft, development of criteria to define minimum flying qualities with emphasis on reconfigurable control systems for fighter aircraft.  This work included flight testing on the Princeton University Variable Stability Navion.

·         Flight control system design for modified and new general aviation aircraft configurations, and numerous flying qualities assurance programs.

·         Principal investigator and project engineer/pilot for several simulation and flight programs to investigate pilot workload in the single-pilot IFR environment for NASA Langley Research Center.   

Mr. Hoh has been employed by Hoh Aeronautics, Inc. for the past 23 years.  HAI is a small consulting firm devoted to the analysis of, and solutions to problems involving cockpit displays, flight control, handling qualities, and human factors considerations for all types of fixed wing and rotary wing aircraft.  Before founding HAI, Mr. Hoh was a Principal Research Engineer at Systems Technology Inc., where he spent 20 years working on similar problems.

Mr. Hoh has performed as an Engineering Test Pilot in support of numerous flying qualities experiments, and new product development including ground based and in‑flight (variable stability) simulations of fixed‑wing (CTOL and VSTOL), and rotary‑wing aircraft.  He has also served as a test pilot on prototype and modified general aviation aircraft.  He holds an FAA Airline Transport Pilot Rating (ATP), is a commercially rated pilot for rotorcraft, and holds instrument and instrument instructor ratings for fixed wing aircraft.  He is Type Rated in the Boeing 737 (Qualified in Classic and New Generation 737).  Mr. Hoh is an FAA Designated Engineering Representative (DER) as Flight Test Pilot, Flight Test Analyst, and Systems and Equipment for FAR Parts 23, 25, and 27.

Back to Home Page