Attachment A - Learjet Acoustic Test Requirements and SOW.pdf

1 Brown, C. and Bridges, J., “An Analysis of Model Scale Data Transformation to Full Scale Flight Using Chevron

Nozzles,” NASA TM‐2003‐212732, December 2003.

SPECIFICATION / STATEMENT OF WORK

1.0 Scope and Background

The NASA Glenn Research Center (GRC) is planning a flight test to be conducted in Fiscal Year 2021 using a Learjet 25 aircraft with CJ610 engines to assess flyover noise levels. Previous tests were conducted in

2001 using a NASA Learjet 251. NASA seeks to repeat a portion of the measurements with improved data acquisition for aircraft position and engine operating conditions. The objective of the test is to measure the noise of constant altitude (500’) flyovers for various engine pressure ratio (EPR) values. Since NASA no longer has a Learjet 25 aircraft, an external source is being sought to provide the aircraft and test coordination. On‐board data collection using Contractor furnished equipment and NASA furnished equipment will be required.

2.0 Requirement Definition

The following differentiates between requirements and other statements contained in this SOW:

Shall This is the only verb used for binding requirements.

Should/May These verbs are used for stating non‐mandatory goals.

Will This verb is used for stating facts or declaration of purpose.

3.0 Aircraft and Equipment Requirements

3.1. Aircraft

For flights specified in this contract, the Contractor shall operate a Learjet 25 aircraft equipped with

CJ610 turbojet engines.

The aircraft shall not be equipped with thrust reversers or hush kits.

NASA will need to know the nozzle diameter of the engine for acoustic calculations.

3.2. Recording of Engine Operating Conditions

The aircraft shall be capable of providing a Global Positioning System (GPS) time‐stamped digital recording of operating conditions for both engines, including Engine Pressure Ratio (EPR), Exhaust Gas

Temperature (EGT) and Engine Rotational Speed in revolutions per minute (RPM). Where applicable, the system should use multiple sensors to provide an average value. It is desirable, but not required, to use existing engine sensors.

The engine operating conditions shall be recorded at a sample rate of at least 3 Hz.

The engine operating conditions shall be recorded continuously for each flight and minimally include the start of the first flyover to the ending of the last flyover.

The Contractor shall provide all digitally recorded data files to NASA in an open data format (non‐ proprietary, text‐based), such as a Comma Separated Values (CSV), or equivalent.

NASA will need to calculate uncertainty bands in the test data. Thus, calibration of the instrumentation used to measure engine operating conditions is required.

The Contractor shall provide an aircraft engine instrumentation calibration plan to NASA for review and approval. The calibration plan should be included in the Contractor’s proposal and be in accordance with the engine manufacturer’s recommendations.

The aircraft engine instrumentation calibration shall be performed by appropriately qualified personnel.

The aircraft engine instrumentation calibration shall be performed within one calendar year prior to the acquisition of flight data.

The Contractor shall provide the aircraft engine instrumentation calibration data to NASA prior to the

Flight Readiness Review defined in Section 6.2

The Contractor’s proposal should give details of the engine operating conditions recording system, sensors used to obtain the measurements, and the plan for calibration.

3.3. Recording of Aircraft Position and Orientation

NASA will provide the Contractor with a Position and Orientation System (POS) that will be capable of providing time‐stamped aircraft position and orientation data. The POS consists of a Computer System

(PCS), an Inertial Measurement Unit (IMU), and a Global Navigation Satellite System (GNSS) antenna.

The Contractor shall perform all necessary engineering and fabrication work to install and operate the

POS in accordance with the system’s User Manual (Appendix III).

An existing aircraft GNSS antenna may be utilized if it is shown to provide an adequate signal for the system.

In order to minimize lever arm errors, the IMU and the GNSS antenna should be located as close as possible to known body frame locations on the aircraft. NASA will need to know the distances and mounting angles between the IMU, GNSS antenna, and the engine nozzle exit location.

NASA will provide technician support to assist with the lever arm and mounting angle measurements.

The NASA technician will also support the software configuration and functional testing of the POS.

The POS will be configured to initialize and log data automatically when power is provided to the system.

The Contractor shall operate the POS to record aircraft position and orientation for all flights.

The Contractor shall visually verify that the POS is operating properly before each flight. Indicator lights on the PCS provide a visual confirmation that the system is powered on and actively logging data within defined accuracy limits.

After visually verifying that the POS is operating properly, the Contractor shall provide the POS a 10 minute period without aircraft movement at the beginning and at the end of each flight. This is required to provide enough known stable data to the computer to resolve ambiguities. Power to the POS should not be interrupted between these periods.

The Contractor’s proposal should give details of the plan for installation and approval of the POS.

In addition to the POS data, the Contractor shall record an electronic flight bag (EFB) “track log” of each flyover and deliver the data in KML and CSV file formats to NASA at the conclusion of each flight. The source for the EFB track log shall utilize a WAAS GPS receiver.

4.0 Flight Requirements

4.1. Aircraft Configuration and Flight Path

The Contractor shall conduct flyovers at a target altitude of 500 feet directly above a ground microphone array. Figure 1 shows a representative flyover test setup with ground microphones.

For each flyover, one engine shall be set to idle while the other engine is set to the desired EPR for the test point. The desired EPR range is between 1.5 and 2.0 with increments of 0.1.

The engine chosen to be idle shall remain consistent for all flyovers.

All flyovers shall be completed with landing gear retracted and the use of flaps should be minimized to only what is necessary for safe flight. The desired flight speed range is between Mach 0.2 (~132 knots) and Mach 0.3 (~198 knots).

The aircraft shall be stabilized before reaching a designated point on the ground in front of the first microphone, then maintain a steady flight path for at least 45 seconds.

The aircraft altitude, speed, power setting, and configuration shall remain constant during the entire flyover.

The acceptable altitude deviation shall be +/‐ 25 feet of the target altitude. The acceptable lateral position deviation shall be +/‐ 25 feet of the microphone array centerline. The acceptable indicated airspeed deviation shall be +/‐ 5 knots from the stabilized airspeed.

The Contractor’s proposal should evaluate the feasibility of the specified acceptable deviations.

The Contractor shall develop flight procedures that emphasize repeatable precision of the EPR setting and flight path. The Contractor shall utilize flight test cards to manually record the following data for each flyover:

Sortie / Run number / Target EPR

Aircraft configuration (flap setting)

Run start/stop times

Altitude (+/‐ deviation)

Indicated airspeed (+/‐ deviation)

EPR

EGT

Engine RPM

In order to minimize errors in the Position and Orientation System, high aircraft bank angles should be avoided for the duration of each test flight.

A notional test matrix is given in Appendix I. The Contractor shall conduct at least one trial flight to provide enough information to finalize the test matrix. The actual test matrix will not be finalized until after the trial flight has verified the desired flight configurations and the estimated time required to complete the testing. The Contractor’s proposal should evaluate the feasibility of the notional test matrix and provide an estimated time to complete each run and sortie.

Figure 1 – Ground Microphone Array

4.2. Trial Flight

The Contractor shall conduct a Flight Readiness Review (FRR) in accordance with Section 6.2 prior to any flights under this contract.

The Contractor shall use the trial flight to determine which EPR set points will need to have flaps deployed, if any. The Contractor should minimize the usage of flaps, but ensure a safe flight configuration within the aircraft’s approved flight envelope at all times.

The trial flight shall also serve to confirm adequate data collection of engine operating conditions and aircraft position and orientation.

The trial flight shall include at least five representative flyovers to confirm the ability to achieve repeatable flight paths within the specified acceptable deviations.

4.3. Test Flights

The Contractor shall conduct a Test Readiness Review (TRR) in accordance with Section 6.3 prior to the test flights.

The Contractor shall conduct the Trial Flight at least one week prior to the Test Readiness Review (TRR).

All government furnished equipment shall remain integrated in the aircraft between the trial flight and completion of the test flights.

The Contractor shall complete the entire test matrix. Contingency flight dates should be planned in case the test requirements are not met on planned flight dates (e.g. weather, equipment, airspace, etc.).

The Contractor shall allow access to the aircraft after each flight to retrieve and download the test data.

4.4. Required Weather Conditions

The test flights shall be conducted on favorable weather days in Visual Meteorological Conditions (VMC) conditions.

The wind speeds between 0 and 500 feet above the microphone array at the test location shall be as follows:

Maximum wind speed less than 13 knots

Average wind speed less than 10 knots

Maximum crosswind component less than 9 knots

Average crosswind component less than 6 knots.

The relative humidity (RH) and temperatures at the test location shall be inside the envelope shown in

Figure 2.

The weather go/no‐go decision for proceeding with a test flight shall be made by a NASA representative using current weather data and weather forecasts acquired by NASA personnel

Figure 2 – Target Relative Humidity and Air Temperature

4.5. Test Location

Prior to contract award, NASA will need to evaluate and approve any proposed test locations.

The test location shall be capable of accommodating the required acoustic and weather measurement systems provided by NASA. NASA personnel will set up and operate all acoustic and weather measurement systems. NASA personnel will require access to the test location for setup of the measurement systems in advance of the test flights. The acoustic measurement systems will consist of the ground microphone array depicted in Figure 1. The weather measurement systems will consist of either a tethered, retractable weather balloon, ground based LIDAR, and/or a small Unmanned Aerial

System.

The Contractor should propose a test location and aircraft flight path that minimizes the noise impact on the surrounding population.

The test location shall have background levels that are suitable for acoustic measurements, as determined by NASA personnel. Depending on the time of year, some level of insect control may be required. The test location shall allow the application of insecticide if necessary.

NASA acceptance of a test location will be subject to typical weather conditions, background noise levels, accessibility for setting up measurement equipment, potential conflicting air traffic, etc.

The Contractor shall identify and obtain all the required approvals, permits, etc. and notify the relevant authorities in order to successfully complete the required test flights at the selected test location. This may include FAA airspace and airport permissions, NOTAMS, etc.

5.0 Commercial Aviation Services Requirements

5.1. Background Information

The services defined in this statement of work were identified as a Commercial Aviation Service to

NASA. A Commercial Aviation Service (CAS) is defined as a full‐service contract agreement through which an executive agency acquires an aircraft and related aviation services (e.g., pilot, crew, maintenance) for exclusive use.

All NASA aircraft operations, including CAS operations, are required to be compliant with NASA

Procedural Requirements (NPR) 7900.3 Aircraft Operations Management Manual. The current revision of the NPR requires CAS operators to hold and maintain an FAA Part 121 or Part 135 Certificate. NASA is reconsidering this requirement and plans to allow CAS operators to demonstrate compliance with applicable Part 135 requirements without holding the Part 135 certificate. This contract will serve as a

“beta test” for demonstration of Part 135 compliance in lieu of certification. NASA recognizes that the current revision of NPR 7900.3 is at variance with the new policy being tested under this contract.

In order to facilitate additional demand for Commercial Aviation Services to accomplish NASA missions, the NASA Headquarters Aircraft Management Division (AMD) is developing a new NASA standard that consolidates all the applicable requirements from NPR 7900.3 and 14 CFR Part 135 that CAS providers must be in compliance with to conduct NASA missions. Appendix IV provides a draft copy of the standard currently under development, NASA‐STD‐7900.3. For continuous improvement of the NASA standard, Contractor feedback is encouraged.

CAS operators that do not hold and maintain an FAA Part 121 or Part 135 Certificate will need to demonstrate how they are compliant with the applicable requirements of NPR 7900.3 and 14 CFR Part

135. In areas that a CAS operator is not compliant, the Contractor may demonstrate an equivalent level of safety or seek a waiver. Waivers for Part 135 requirements may be approved by NASA GRC. Waivers for NPR 7900.3 requirements must be approved by NASA Headquarters AMD and would require additional levels of approval. Any areas of non‐compliance with the stated requirements should be well‐ coordinated in advance of the contract award. A pre‐contract award inspection (See Section 5.4) will assist in identifying any areas of non‐compliance.

NASA GRC is willing to work with contractors that exhibit areas of non‐compliance and it should be emphasized that the disclosure of non‐compliance will not immediately disqualify a bidder from their ability to win the contract.

5.2. General Requirements

All flights performed under this contract shall be conducted as public‐use aircraft operations under

NASA’s operational and airworthiness authority.

The operator of an aircraft that has performed a public aircraft operation for NASA shall not return the aircraft to service in civil operations without demonstrating that the aircraft meets all the criteria as prescribed by FAA regulations to hold its FAA airworthiness certificate. The Contractor shall be responsible for following all FAA requirements for returning the aircraft to civil status. For more information, the Contractor should contact their local Flight Standards District Office (FSDO).

The Contractor shall comply with NASA Procedural Requirements (NPR) 7900.3 Aircraft Operations

Manual.

The Contractor shall not conduct any flights under this contract until they have received a NASA

Airworthiness Certificate or NASA Statement of Airworthiness, a GRC Safety Permit, and a successful

Flight Readiness Review.

5.3. Pilot Experience

All pilots performing flights under this contract shall have logged a minimum number of hours of aeronautical experience as shown in Table 1.

The Pilot‐in‐Command (PIC) shall hold and maintain an unrestricted FAA Airline Transport Pilot

Certificate and a current type rating as PIC for the Learjet 25.

The Second‐in‐Command (SIC) shall hold and maintain at least an FAA Commercial Pilot Certificate with an Instrument Flight Rating and have a current type rating as PIC for the Learjet 25.

Table 1 – Pilot Experience

Pilot‐in‐Command (PIC) Second‐in‐Command (SIC)

Total hours 1,500 500

Total hours in Learjet 25 500 100

Total hours Pilot‐in‐Command 500 0

Total hours Pilot‐in‐Command in Learjet 25 100 0

5.4. Environmental / NEPA Requirements

All work performed under this contract shall be in compliance with all applicable Federal, state, and local environmental regulations. Pending location of testing (including trial flight) and/or a scope change, further National Environmental Policy Act (NEPA) analysis may be warranted. Project personnel shall work with the GRC NEPA Manager to ensure appropriate NEPA coverage and public outreach.

Additionally, contractor shall ensure coordination has or will be completed with the FAA to operate aircraft at desired research noise levels. Coordination includes receipt of a noise waiver by the FAA.

5.5. Contract Surveillance and Inspections

In order to ensure compliance with contract requirements, NASA reserves the right to conduct no‐notice surveillance inspections of all maintenance and flight efforts performed under the contract, regardless of Contractor/Subcontractor status. The Contractor shall support these surveillance activities and ensure

Subcontractor compliance as required.

The Contractor shall provide and make available all applicable flight operations and maintenance manuals, aircraft logbooks, and personnel training records.

The Contractor shall undergo an inspection by NASA personnel prior to contract award. This inspection will review the operator’s aircraft, flight operations, maintenance practices and overall capability to comply with NASA standards and mission requirements.

In order to greatly facilitate the inspection, the Contractor’s proposal should include a self‐evaluation of compliance with requirements using the provided Compliance Evaluation Document in Appendix V, or an equivalent compliance matrix.

5.6. Airworthiness Requirements

The Contractor shall hold and maintain a NASA Airworthiness Certificate or Statement of Airworthiness for all flights under this contract.

If the aircraft currently holds and maintains an FAA standard airworthiness certificate, NASA will review the aircraft configuration and issue a NASA Statement of Airworthiness.

If the aircraft currently holds and maintains an airworthiness certificate other than a standard airworthiness certificate, NASA will review the airworthiness of the aircraft and issue a NASA

Statement of Airworthiness or a NASA Airworthiness Certificate. In this case, the Contractor shall identify any previous alterations or maintenance practices that were not performed in accordance with

14 CFR Part 91 and 14 CFR Part 43. NASA must review and approve any deviations prior to issuance of a

NASA Statement of Airworthiness or NASA Airworthiness Certificate.

All aircraft alterations performed under this contract shall be completed in accordance with 14 CFR Part

91 and 14 CFR Part 43, except that all descriptive and substantiating data for the alterations shall be reviewed and approved by NASA. The Contractor may seek parallel FAA approval of aircraft alterations to facilitate the aircraft’s return to civil aircraft status if desired.

The Contractor shall obtain and operate in accordance with a GRC Safety Permit for all flights under this contract.

A GRC Safety Permit requires a Hazards Analysis in accordance with MIL‐STD‐882 to identify any real or potential conditions that could cause injury, illness, or death to personnel; damage to or loss of a system, equipment or property; or damage to the environment. The Hazards Analysis will include a risk assessment and identify mitigation strategies to bring risk to acceptable levels (i.e., design, safety devices, warnings, procedure, training, or other methods). The Contractor shall support NASA in the development of a Hazards Analysis by identifying hazards and mitigation strategies.

6.0 Reviews

6.1. Airworthiness and Safety Review

The Contractor shall support an Airworthiness and Safety Review meeting.

The Airworthiness and Safety Review shall serve as an opportunity to provide the GRC Aviation Safety

Committee enough information to issue a GRC Safety Permit and recommend the issuance of a NASA

Airworthiness Certificate or NASA Statement of Airworthiness. The NASA GRC Aviation Safety

Committee serves the function of an Airworthiness Review Board as described in NPR 7900.3.

The Contractor shall provide a data package in support of the Airworthiness and Safety Review at least one week in advance of the meeting.

The data package shall include:

Documentation of compliance with the Commercial Aviation Services requirements and rationale for seeking NASA approval of any waivers

All descriptive and substantiating data for aircraft alterations to be completed

An overview of the planned flight operations

Hazard analysis and planned mitigations

Descriptive data describes the design of the repair or alteration. It should include references to installation methods, materials, fabrication processes, dimensions, and tolerances. It may also include intended function and how the alteration is appropriate to the aircraft. Descriptive data typically includes:

Drawings and specifications;

Information on dimensions, materials, and processes;

Airworthiness limitations (AL), if applicable; and

Documents required by the airworthiness requirements such as instructions for continued airworthiness (ICA) and airplane flight manuals.

Substantiating data shows that the design complies with the applicable regulations and that all appropriate technical considerations have been addressed. Examples of substantiating data can be: test results, computations, and other information necessary to show that descriptive data meets the applicable requirements.

The Airworthiness and Safety Review shall also include a NEPA review by the GRC NEPA manager.

6.2. Flight Readiness Review

The Contractor shall conduct a Flight Readiness Review (FRR) prior to the first flight under the contract.

The objective of the FRR is to provide a comprehensive assessment of aircraft airworthiness, installed equipment, and operational procedures to assure overall readiness and operation of the aircraft and flight systems.

Areas of consideration shall include:

a. Science mission requirements

b. Flight operations procedures

c. Operational Go/No‐Go criteria

d. Pilot qualifications, flight operations training, and flight manuals

e. UAS operations requirements

f. Aircraft configuration

g. Aircraft maintenance

h. Science payload and operations

i. Payload combination

j. Status of reviews

k. Special weather conditions

l. Science functional flight test plan

m. Mishap Preparedness Contingency Plan (MPCP).

6.3. Test Readiness Review

After the Trial Flight and resolution of all discrepancies, the Contractor shall hold a Test Readiness

Review (TRR) prior to the Test Flights.

The objective of the TRR is to review the final test matrix and any changes to the areas of consideration covered during the FRR.

7.0 Reporting Requirements

The Contractor shall provide Bi‐Weekly Progress Reports that include at a minimum:

Accomplishments / work completed for the reporting period

Any issues or programmatic risks and mitigation strategies

Potential schedule changes

8.0 Summary of Deliverables

Table 2 – Summary of Deliverables

Deliverable Due Date

Status Reports Every two weeks

Airworthiness and Safety Review Package 1 week before Airworthiness and Safety Review meeting

Engine Instrumentation Calibration Data Flight Readiness Review

Recordings of Engine Operating Conditions At the conclusion of each flight

Recordings of Aircraft Position and Orientation At the conclusion of each flight

Track Log KML files At the conclusion of each flight

Completed Flight Test Cards At the conclusion of each flight

9.0 Government Furnished Equipment

The Government will furnish the items shown in Table 3 to the Contractor. Any Government Furnished

Equipment shall be returned in a working condition within 14 days after the completion of the final test flight.

Table 3 – Government Furnished Equipment

Document/Part # Title

POS AV 510 Applanix POS AV 510 Position and Orientation System

10.0 Schedule Milestones

Table 4 – Schedule Milestones

Task / Milestone Constraints Payment Schedule

Contract Award

Airworthiness and Safety Review Meeting

25 %

Flight Readiness Review After permit issued ‐

Trial Flight After FRR ‐

Test Readiness Review >1 week after Trial Flight ‐

Test Flights After TRR 75 %

The Contractor’s proposal should provide a tentative schedule to include target milestone dates. NASA desires to complete flight testing by October 2021, but recognizes the schedule is subject to aircraft availability and COVID‐19 restrictions.

11.0 Cost Breakdown

The Contractor’s cost proposal should provide a summary of costs in the following categories:

Cost to configure aircraft for test flights (i.e. Non‐recurring engineering cost) Cost to perform flight operations Any additional costs incurred to become compliant with NASA standard for CAS operators

12.0 Appendices

I. Notional Test Matrix

II. Position and Orientation System (POS) Data Sheet

III. Position and Orientation System (POS) User Manual

IV. DRAFT NASA‐STD‐7900.3 NASA Commercial Aviation Services (CAS) Requirements

V. Compliance Evaluation Document – NASA‐STD‐7900.3