t-45 single engine airstart testing over water lcdr k. sproge lcdr m. burks ms. j. mcateer
TRANSCRIPT
T-45 Single Engine Airstart Testing Over
Water
LCDR K. Sproge
LCDR M. Burks
Ms. J. McAteer
Intentional Engine Shutdowns?
The Question: Can single engine airstart testing be safely conducted over water at Pax river?
• Two seat - Tandem
• Single engine
• Carrier capable jet trainer
• Wing
– Moderately swept
– Full span leading edge slats
– Double slotted trailing edge flaps
• Flight controls
– Hydraulic Stabilator and Ailerons
– Mechanical rudder
– Control augmentation system
– Speed Brake
T-45 Aircraft Description
We took the BAE Hawk
And Made A Few Minor Changes
T-45 Aircraft Emergency Systems
• Ram Air Turbine (RAT)– Powers Hydraulic Flight Controls Only
• Emergency Flap Extension– Full flaps Only– No Slats
• Emergency Landing Gear Extension– Main Landing Gear Doors remain fully opened– Nose Landing Gear Doors actuated electrically to within
10 deg of fully closed
• Aircraft essential bus powers: – Limited Aircraft Systems– Instrumentation System
Flight Test Aircraft System Modifications
• Instrumentation system installed to monitor engine and aircraft parameters
• O2 pallet installed for all high risk testing
– No OBOGS engine out
O2 Pallet
• Installed in the aft cockpit
• Approximately 200 lb
• Provides continuous O2 to the pilot
• Controlled via OBOGS switch
• Good glide performance
• Reasonable approach speed
• Arresting hook
• Limited maneuverability
• Nosewheel steering unavailable
• Directional control issues during crosswind landing
• No anti-skid
• Limited brake applications
T-45 Flameout Handling Qualities
A History of Stall/Surges
• During use as a trainer, two major areas were identified as high risk for engine anomalies– Approach Turn Stall Maneuvers (Fam stage)– Air Combat Maneuvering (ACM stage)
Stall / Surge Regions
“ACM” Type Surges: High AOA, Fixed or Variable RPM, Cruise Config“ATSM” Type Surges: Moderate AOA, Variable RPM, PA Configuration
• 1987-1993
• 1997-1998
• 2000-2005
• 2007-Current
• T-45 EMD engine tests, follow-on engine tests, and HAOA tests were conducted at Edwards AFB
• Surge Mitigation Program conducted at NAS PAX
• Integrated Surge Mitigation Program conducted at NAS PAX
• Hot Section Reliability Improvement Program (HSRIP) conducted at NAS PAX
T-45 Engine Testing
Initial Surge Mitigation Program(1996-1998)
• F405-RR-401 engine with known airstart capabilities– Turbine exit area modification
• Abrupt Pulls and Approach Turn Stalls
• Airstarts (2) conducted to verify airstart capability– Heart of envelope
• Potential for AFO due to surge or flameout
Initial Surge Mitigation Program AFO Planning
• Modified NATOPS Precautionary Approach (PA)– Based on NATOPS/Contractor provided glide
model
– Pilot carried card
• 32 Engine surges
Integrated Surge Mitigation Program(2000-2005)
• Modified Inlet / Modified Fuel Control– F405-RR-401 engine with known airstart capabilities– Abrupt pulls– Steam ingestion – High cross-wind testing
• Airstarts (3) conducted to verify airstart capability– Heart of envelope
• Potential for AFO due to engine surge, flameout or unintentional OCF
Integrated Surge Mitigation Program AFO Planning
• Developed AFO communication protocol– Control room and test aircraft
• Developed glide profile intercept method – Above 20k ft establish 300kt for windmill
airstart– Intercept 195 kt below 20k-ft– Modified for different configurations
• Verified NATOPS glide profiles• 62 Surges (1 Locked Stall requiring
shutdown)
Hot Section Reliability Improvement Program (HSRIP), 2005-Current
• HSRIP to replace F405-RR-401– Adour Mk 951 variant – -401 fan and compressor– Redesigned combustor– Turbine– Nozzle– FADEC– Hydro-mechanical backup fuel control– 4,000 hr
HSRIP Test Requirements
• Airworthiness• Full airstart envelope verification• Airstart envelope expansion• Airplane performance verification• Steam ingestion• Carrier Suitability• Intentional Stall/Surges• High AoA• Fleet representative maneuvers
Hot Section Reliability Program(2005-Current)
• HIGH Potential for AFO – Intentional Shutdowns – Backup fuel control testing– Airstart envelope expansion – Testing FADEC logic
• Automatic surge detection and recovery
• Automatic flameout detection and recovery
AFO – Parallel Entry
HIGH KEY5,000 FEET AGL195 KCAS
START TURN5,000 FEET AGL195 KCAS
LOW KEY3,000 FEET AGL, 180 KCASBANK ANGLE – 35 DEGREES 1.5 NM ABEAM1750 FEET DOWNWIND FROM END OF RUNWAYEMERGENCY EXTEND LANDING GEAR
90 – DEGREE POSITION1,500 FEET AGL, 170 KCASBANK ANGLE 35 DEGREESEMERGENCY FLAPS - DOWN
45 – DEGREE POSITION1,000 FEET AGL, 165 KCASBANK ANGLE 25 DEGREES
AFO – Perpendicular EntryHIGH KEY5,000 FEET AGL195 KCAS
START TURN5,000 FEET AGL, 195 KCASBANK ANGLE 25-35 DEG
LOW KEY3,000 FEET AGL, 180 KCASBANK ANGLE – 35 DEGREES 1.5 NM ABEAM1750 FEET DOWNWIND FROM END OF RUNWAYEMERGENCY EXTEND LANDING GEAR
90 – DEGREE POSITION1,500 FEET AGL, 170 KCASBANK ANGLE 35 DEGREESEMERGENCY FLAPS - DOWN
45 – DEGREE POSITION1,000 FEET AGL, 165 KCASBANK ANGLE 25 DEGREES
AFO – Abeam Entry
LOW KEY3,000 FEET AGL, 180 KCASBANK ANGLE – 35 DEGREES 1.5 NM ABEAM1750 FEET DOWNWIND FROM END OF RUNWAYEMERGENCY EXTEND LANDING GEAR
90 – DEGREE POSITION1,500 FEET AGL, 170 KCASBANK ANGLE 35 DEGREESEMERGENCY FLAPS - DOWN
45 – DEGREE POSITION1,000 FEET AGL, 165 KCASBANK ANGLE 25 DEGREES
ABEAM3,000 FEET AGL, 195 KCAS1.5 NM ABEAM
AFO- Straight In5,000 FEET AGL5 NM FROM END OF RUNWAY195 KCAS
3,000 FEET AGL3 NM180 KCASEMERGENCY EXTEND LANDING GEAR
1,500 FEET AGL, 1.5NM FROM END OF RUNWAY,165 KNOTS, EMERGENCY FLAPS - DOWN
The Profile Works!
IDENTIFY HAZARDS
• T-45 AFO approaches prohibited
• AFO over water with one available field
• Decompression sickness
• Airspace/traffic conflicts when returning AFO
• T-45 ground handling characteristics
HSRIP Risk Mitigation Procedures
• T-45 AFO prohibited– CNAF waiver required
• Provided evidence of safe profiles and training/currency measures
– Referenced in NAVAIR flight clearance– Waiver allowed for pilot training/proficiency
HSRIP Risk Mitigation Procedures
• AFO over water with one available field– Test procedures refined over the course of several
programs. – Simulator
• Communication protocol • AFO profile intercept method• Pilot/Test Team training
– Pilot Currency• SFO training flight• At least one SFO in a 14 day period • SFO following takeoff for all flights with high risk test
points
HSRIP Risk Mitigation Procedures
• AFO over water with one available field– Glide profile monitor
• Required for all high risk testing
• All high risk test points must be conducted within glide distance to the field
• Must be conducted within exclusive use airspace
• Modified AFO communication protocol (DME) and profile intercept method
– Wind considerations
T-45 No Engine Glide (No Wind)
10K / 8NM
20K / 24NM 30K / 42NM
40K / 60NM
HSRIP Risk Mitigation Procedures
• Decompression sickness– 1 shutdown above 25k per day
– Pre-breathe 100% 02 30 min prior to shutdown
• Airspace/traffic conflicts when returning AFO– Tower/Baywatch training with test team– Tower/Baywatch briefed prior to each flight event– Chase assumes ATC communication – Exclusive use airspace
HSRIP Airstart Example
• Prior to takeoff– Field Considerations
• Crosswind limits (< 10 kt)
• Arresting gear (short and long field)
• Available runways (RWY 32 required for straight-in)
• SAR Condition
– Area Considerations• Exclusive use for “high-risk” test points
HSRIP Airstart Example
• Communication checks– Direct radio between test aircraft, chase, TC,
FTE’s, and DME monitor – Hot mic from test aircraft – Hot mic broadcast from telemetry center to
chase (hot mic to chase)
• Post takeoff– Execute SFO
HSRIP Airstart Example
• Test point setup– Winds
• Test aircraft provides winds– at test condition
– max altitude (test point setup)
• Glide monitor determines maximum DME – aircraft configuration
– wind speed/direction
• TC relays
– Test point executed with less than 90 deg turn to make field
HSRIP Airstart Example
• TC, Test aircraft, and chase make ready call
• Propulsion FTE takes comm lead for test point – Provides clearance to conduct test point,– Executed when on conditions and within DME
HSRIP Airstart Example
• After FTE clears throttle off ... – Chase calls DME every 2 nm– Glide monitor reports minimum altitude– Propulsion monitors airstart parameters and engine
status
• Unsuccessful airstart– Propulsion recommends airstart type– Chase and glide monitor continue comm sequence– Test aircraft monitors profile
• Option to change to straight-in
– Return to field for AFO approach– Chase handles all ATC comms
Airstart Communication Example
SFO/AFO Lessons Learned
• Glide performance• Data dropout
– Test point location corresponds to drop out area– Several airstarts with no data– Telemetry center implemented best-source select with
multiple receiving antennas
• Loss of comm– Backups ready– Verify continuously
• Winds• New personnel
QUESTIONS?