Functional Statement for an Airborne Turbulence Detection System

1. Functional Statement for an Airborne Turbulence Detection System Detect and alert occupants/aircrew to a potentially hazardous turbulence encounter with sufficient lead time as to permit passengers and flight attendants that are not seated to promptly return to be seated and fasten their seat belts. Functional Requirements for Radar 80% detection at approximately 4 miles (min.) assuming 8 miles per minute (30 seconds) (moderate/severe turbulence @ 10,000 feet and above). - Reflectivity greater or equal to 15 DBz Less than 20% nuisance alarm rate False alarm at 10-04/hour Optional system with no mandated requirement No requirement to automatic alert cabin/flight attendants Must provide an aural and visual (discrete and unique) alert Interface to master caution and warning not required. Interface to EICAS/ECAM not required. Interface to flight recorder not required.

2. Functional Statement for an Airborne Turbulence Detection System Detect and alert occupants/aircrew to a potentially hazardous turbulence encounter with sufficient lead time as to permit passengers and flight attendants that are not seated to promptly return to be seated and fasten their seat belts. Functional Requirements for Long Term-Radar and Lidar/Convective and CAT Procedures/guidance relative to turbulence warning times (i.e. 0-30 sec, 30-60 sec. etc). 90% detection at 1 minutes? Tasks/Activities leading to realization of Functional Requirements

3. Tasks/Activities leading to realization of Functional Requirements • Verify functional requirements through simulation and flight studies CY01-02? • (NASA/Industry?) • 2. Implementation of NASA demonstration program • Sensor Technologies • Integrate one external source of information • Alerting capability for flight deck and cabin under • current guidelines • Hazard metric development • 2. Implementation of demonstration program on commercial aircraft(s) CY01-02? • Sensor Technologies – data collection (near-term CY01 • implementation) • 2. Integrate one external source of information

4. Questions that need to be answered • How much alerting time is required to produce an increase in safety (time required for adequate crew/passenger response, cabin secure, etc.)? • Answer: Secure Cabin Team will address as well as investigate cockpit simulation work being planned by NASA/CAMI. NASA and CAMI may have the means for future sim capabilities. • What kind of aural/visual alerts should be given to the cockpit (and cabin?) crew? • Integration with other alerts in cockpit • Answer: Integration is desirable but not required. Investigate aural alerts in conjunction with other alerts (George Lyddane, FAA) • Icons, colors, etc. • Answer: Treat as a warning (at least a level 3) due to immediate pilot response required. Discrete light should be red if used? • Answer: Future icon revisions held in Parking lot (Display Set Working Group) • What are sensor detection capabilities at 80% reliability (dbz, warning time, sensor characterization)? • Answer: NASA Turbulence Program in conjunction with other government and industry activities

5. Questions that need to be answered • What are the procedures that should be followed by the flight crew and/or cabin crew given different “levels” (warning time, turbulence intensity…) • Can we differentiate between turbulence intensities (i.e. moderate and severe) and do we have to? • What is turbulence intensity based on g-loads, others? Can we reach consensus on light, moderate, severe, extreme? • Should we investigate turbulence effect based on aircraft-type and to what degree?

6. Barriers • Liability issues in regards to collecting data from a non-interference turbulence sensor system. • Will bring forth issue to NASA-FAA-NWS Advocacy group by Kirk Baker and Shari-Beth Nadell • Data recording funding is not in current plans • FOQA data with weather radar data input needed on sufficient number of a/c • Implementation plan needed for advocacy. The following members will pull together such a plan: • Larry Cornman-NCAR • Bill Weist-Honeywell/GE (Lead) • Roland Bowles-Aerotech • Kirk Baker-FAA • Roy Robertson-Rockwell Collins • Steve Harrah (placeholder)-NASA LaRC • Carl Knable (placeholder)-UAL • Tom Fahey (placeholder)-NWA • Above mentioned data will provide a statistically-relevant data base for radar validation (nuisance, alerting times…better defined) versus case study development supplied by NASA flight campaign as well as improve business case to the airlines/vendors.

7. Sensor System Thresholds and Hazard Metrics(The following will be used as initial “move forward” guidelines until further studies indicate otherwise as directed by the FAA) • What hazard metric is needed to correlate hazard to a/c. Answer: RMS normal load g- sigma delta n • What threshold (“what fires the light”) is needed to alert pilot of hazard . Answer: Moderate/Severe: .3 g RMS is a must alert .2 g RMS is a may alert One stage alerting is sufficient. Activities to be performed: • A/C class hazard metrics variations (NASA) • Level of nuisances, false alarms etc. for particular threshold (NASA/Industry/Airlines) • Discrimination of RMS normal g between moderate and severe (NASA) • Alerting Time required for actions (Secure Cabin Experiment Team) • Define an “event” and what constitute an “hit” (NASA) Issues: • Filtered a/c inputs: vendor provide altitude and air speed only • A/C response model availability (FAA will advocate with ties to in-situ needs/NASA-Boeing Agreement (POC John White/LaRC)

8. Certification Scenarios • Von Karman block and cloud modeling (with embedded sub-grid) currently being performed by NASA. Cloud modeling already performed with TWA DC-9, AA DC-9, USAir 737. • Need to pull together the right team to select the right accidents cases. • Test cases on the boundaries of the envelope must be done not just for accident cases. • NASA LaRC 757 may be ideal platform to obtain the ideal test cases/boundaries to envelope. • NASA needs to pull together the Turbulence sub-teams (I.e. detection and characterization sub-teams) towards addressing certification scenarios/models. ACTION: NASA 757 test matrix will be available (www.grc.nasa.gov/WWW/grcavsp/Turbulence1) to workshop participants for comments and future discussions-Shari-Beth Nadell • Aside for above models we need the following information • Thresholds • Standard aircraft response model- 757 • Boundary conditions based on sensor limitations needed for above models- Detection PDT action item • Need to use analytical models to create baseline minimum performance specification- Bill Weiss, Roy Robertson, Steve Harrah • ISE can be used to better define performance standards. • FAA establishes performance criteria against scenarios.

9. Next Workshop • Secure Cabin Drill report • In-service data implementation plan/status • Progress toward evaluating functional requirements • Lidar/combined system requirements discussions • Workshop #3 – May 1-3, 2001 at FAA CAMI, Oklahoma City • B757 test results analyses • Status/Progress on cert. Criteria • Strawman requirements document (Kirk) • Draft vendor PSP • Organizers: Ken/Julie Larcher, Shari-Beth Nadell, Victoria Briscoe

10. References Sussman, E.D., Pollard, J/K, Mengert, P.& DiSario, R. (1994). Study to Establish the Ride Comfort Criteria for High Speed Magnetically Levitated Transportation Systems. US DOT, Report #DOT/FRA/NMI-94/1 Bass, E.J., Campbell, R.H, Castano, D.J., Jones, W.M., Kvam, P. An Analysis of Commercial Airline Pilot Turbulence Assessment in Full Motion Simulator, 19th Digital Avionics System Conference, October 7-13, 1999. Philadelphia, PA