T-45 Single Engine Airstart Testing Over Water LCDR K. Sproge LCDR M. Burks Ms. J. McAteer

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




AFO – Abeam Entry




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


• 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


• 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


• 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


• 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


• 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


• 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


• 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?

Documents

T-45 Single Engine Airstart Testing Over Water LCDR K. Sproge LCDR M. Burks Ms. J. McAteer