Description of Driving Event:
Aging NASA Training Aircraft
Lesson(s) Learned:
NASA aircraft used for both Space Shuttle operations and astronaut training are increasingly out of date and, in several respects, may be approaching the unsafe. This is noticeably so in the case of the Shuttle Training Aircraft (STA) and T-38 aircraft.
Recommendation(s):
Continue to execute and accelerate as much as possible the current plans for the modernization and safety assessment of astronaut training aircraft.
Evidence of Recurrence Control Effectiveness:
NASA believes that the current aircraft used as astronaut training aircraft are maintained in a safe condition. NASA remains committed to safe operation of all the training aircraft. Measures to ensure that the NASA T-38's and STA's used for astronaut training are maintained in a safe configuration and in good material and structural condition are in place. A summary of current efforts is as follows: T-38: NASA's approach to maintaining and modernizing the T-38's is two-fold. The first approach consists of maintaining and upgrading the fleet in consonance with the USAF programs. (The USAF Air Training Command plans to use the T-38 for flight training to 2020 and beyond.) This includes engine component upgrades, replacement of structural members, including entire wings, and comprehensive nondestructive inspections at prescribed intervals. Additionally, a 1995 NASA contracted limited damage tolerance assessment study confirmed that the aircraft structures can be maintained with standard inspection criteria at intervals. The second approach encompasses NASA unique programs that are tailored to the specific use of the NASA T-38's for the astronauts' space flight readiness training. NASA unique programs include: - An Avionics Upgrade Program which modernized the communications and navigation systems, replaced high failure rate and outdated avionics, and added a weather radar, a flight management system, an altitude alerter, and modern controls and displays. This program has been completed on the T-38 operational fleet and has resulted in a redesignation of the USAF T-38A to the NASA T-38N. Intended follow-on avionics enhancements, as they become practical and economically acceptable for the T-38N, includes modification to a Global Positioning Satellite (GPS)-based flight management system and the incorporation of the terminal collision avoidance system.
- Modified engine inlets to increase the takeoff performance and the margin of safety of the aircraft over the standard configuration. A successful flight test program on the prototype aircraft has been completed, and the T-38 corrosion control and structural modification team at El Paso, Texas, has completed the first pilot production aircraft.
- Replacing the T-38 ejection seats with state-of-the-art seats that will meet the full range of astronaut anthropometrics and are highly reliable, zero-altitude/zero-air-speed capable.
- A just completed flight test of an engine ejector modification designed to improve the in-flight range of the T-38. This modification should enhance both efficiency and flight safety.
NASA will continue to evaluate new programs and seek new initiatives to meet the requirements as they evolve, such as adding avionics for compatibility with the future free flight concept in the air traffic control system. STA: NASA has four STA's and one spare Gulfstream II (GII) that will be modified into an STA when it is either required by the Shuttle flight rate or in the event that one of the four STA's becomes unusable. In regards to STA maintenance, the initial aircraft maintenance and inspection program developed by the aircraft manufacturer, Grumman, in concert with NASA engineers included a short interval comprehensive nondestructive inspection program. That maintenance program was designed to ensure close monitoring of the structural health and material condition of the STA, which was and is operated in a much more demanding flight regime than the corporate GII aircraft. Furthermore, a 1993 and 1994 NASA contracted effort with Science Applications International Corporation resulted in the determination that the STA fleet can operate safely within the established flight training profiles and that structural integrity can be monitored through the ongoing inspection program. Modernization of the aircraft includes recent avionics systems upgrades with an incorporated differential GPS approach guidance system and the modification of the Shuttle simulation system to include the orbiter MEDS to provide astronaut pilot orbiter landing training for MEDS-equipped orbiters. Based on the basic STA GII remaining service life and the NASA maintenance program, there should be ample service life remaining on the four aircraft to provide astronaut training well into the second decade of the 21st century. However, repair and component costs due to systems obsolescence or frequency of structural repairs could conceivably indicate a need for either systems redesigns or an earlier selection of a replacement aircraft type.
Documents Related to Lesson:
N/A
Mission Directorate(s):
- Space Operations
- Exploration Systems
Additional Key Phrase(s):
- Aerospace Safety Advisory Panel
- Aircraft
- Logistics
- Policy & Planning
- Training Equipment
Additional Info:
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