anthony p. (tony) taylor technical director airborne systems inc the system approach to spin stall...
TRANSCRIPT
Anthony P. (Tony) Taylor
Technical Director
Airborne Systems Inc
The System Approach to Spin Stall Parachute Recovery – An Update at 10+ Years
OutlineOutline
What is a Spin Stall Parachute Recovery System (SSPRS) ? History of the System Approach to SSPRS at Irvin
The Challenge The Result - An Outline of a Basic SSPRS System
Aircraft Installed Equipment Ground Support Equipment and Integrated Testing Well Developed Installation and Operation Manuals
Interlaced Throughout – Initiatives to Address the Requirements of the VLJ Market, and Recent Work on the Lightning II
Lessons Learned The Evolution of Systems Since the ‘First System Approach’ Examples of Operational Incidents, Major and Minor, Positive and Negative
Major Events, safety related Minor Events, maintenance level but also safety related
Some Operational Tests – Your Personal Fam Flight!
A View of a SSPRSA View of a SSPRS
Attach / ReleaseMechanism
Cockpit ControlPanel
Parachute / MortarSystem
Trailing Cone Cutter Aircraft wiring / componentsSupport Structure
What is A SSPRSWhat is A SSPRS Simply put, a parachute attached to the aircraft tail that lowers the AOA and
thus restricts the Spin or Stall Great Example in next Video
For Fairness, Other Approaches Exist Rockets – Wing Tip or Tail Mounted Mass transfer – Forward in some cases, Aft in other cases Deployable Fins at the Aircraft Tail
While these have been studied and used occasionally, the Parachute method is the Aerospace industry standard
One other significant note, many Business Jet Mfg also use another parachute for high speed drag augmentation. Mach Tuck and Deceleration out of Flutter points, as well as Attitude Control Similar approach as discussed herein however details of the situation can be
significantly different
Next Slide, a Video of an Actual RecoveryNext Slide, a Video of an Actual Recovery
This is one of my favorite videos – you will see why ! Aircraft: F-5E – First Spin Test Location: EAFB – Ground to Air Video with Long Lens Pilot: Dick Thomas
Actually got to ask Dick about this test Summary: Tried all the Adverse combinations (Stick and Rudder) and all
the Proverse Combinations and all in between – Finally, and Dick reported pretty late, went to the parachute.
F-5E Flight Test VideoF-5E Flight Test Video
History of the System Approach at IrvinHistory of the System Approach at Irvin
Circa late 1995, Bombardier Flight Test Center (BFTC) invites Irvin to a meeting to review system requirements for the Global Express aircraft At that time, Irvin provides only the Parachute and Mortar Irvin is providing equipment for Canadair Aircraft only
Lear Jet Aircraft are provided by another company BFTC has recently been created to Flight Test all Bombardier Aircraft
Canadair has suffered in the past two (2) significant system failures CRJ Incident Challenger Incident Both caused loss of aircraft and some/all of flight crew
The Challenge: BFTC Challenges Irvin to become System Level provider of all the SSPRS
Equipment Pete Reynolds outlines the basic system challenges BFTC and Irvin Engineers Define the Basic Requirements, and Recognize a
Significant, but interesting Challenge
The Basic RequirementsThe Basic Requirements
Original Requirements As Outlined with BFTC: Dual Power Source Quad Electrical Circuits – Where Possible
Dual for Pyro Lock Reversible Parachute Lock Fast Acting Additional Parachute Lock Large Deploy Handle
Rotate to Lock Pull to Deploy Parachute
Fast Acting Lock – Immediate Trailing Cone Cutter – Immediate Parachute Deploy – 0.5 Second Time Delay
The Basic Requirements (continued)The Basic Requirements (continued)
Smaller Jettison Handle Covered by Deploy Handle Electrical Interlock
Simple Lights Green Parachute Locked and Passing BIT White Parachute Unlocked – All position Switches Agree Green Light Repeater on Glare Shield
Built In Test Power Pyro Circuits Reversible Lock Switch Position
Irvin Response at the meeting: ‘This is going to be hard, but it is going to be darn neat when it is finished!’
The ResultThe Result
The result, both in the initial response and with years of maturation has been (what most consider) a marked improvement in the reliability, safety and testing of SSPRS systems
Significant Results 1 Aircraft Recovery Several Aircraft ‘Events’ which were ‘Non-Events’ Tens of BIT detected faults which were real issues, resolved
both before and during flight Several Service Related Incidents – Including One Very
Recent – Which Result in Safety Notices and Procedure/Equipment Updates
Parachute and MortarParachute and Mortar The Parachute and Mortar is the Irvin
preferred installation Conical Ribbon (or other Ribbon) parachute
is the preferred approach due to inherent strength and excellent stability
Direct mortar deployment of the parachute provides the highest reliability approach
High Energy Minimal part count
Mortar also provides an efficient mounting container
Relatively well weather protected Easily mounted to aircraft structure
Images at the left provide examples of: Initial Parachute Pack Deployment Fully Deployed Parachute Thanks to EAFB F-22 Raptor CTF !
VLJ Market – Mortar vs. Other DevicesVLJ Market – Mortar vs. Other Devices
Parachute Mortars have many positives Highly Reliable Energetic deployment Provide a Parachute Compartment
And at least one negative Cost
For one recent VLJ Customer Airborne has agreed to use Tractor Rocket Deployment – Customer is very use to tractor rockets
Airborne is pursuing a program to become more comfortable with the devices for the future
Attach/Release Mechanism (ARM)Attach/Release Mechanism (ARM) Two designs exist that cover aircraft from
relatively light business jet through F-22/F-35 Functional features are the same for all
variants, these include: Reversible lock through a servo motor Parachute retention through a low force
shear pin that will release the parachute if not ‘Locked’ to the aircraft
Position switches for feedback of reversible lock position
Pyro locking pin for fast acting (and redundant) lock when Recovery Parachute is deployed
Redundant pyrotechnic cutters for parachute release
These are much more reliable than any mechanical based release
Full value of this approach is realized when reviewed with the control technique (next chart)
ATTACH RELEASE MECHANISM
Smaller/Lower Cost ARMSmaller/Lower Cost ARM
Small Probably = Lower Cost Current Low Force ARM is not that
large, but price could be reduced IRAD Effort Planned for this year to
work to reduce price and size
Control SystemControl System
Provides simple PVI that has eliminated all previously known errors
Rotate Deploy Handle to Operate reversible, servo-motor lock
Pull Deploy Handle – begins Deployment sequence Irreversible Sequence Permanent Pyro-Lock fires to provide
additional parachute lock Trailing Cone Cutter releases that device (if
installed) – Business Jet Issue Parachute deployment is delayed 0.5
seconds to allow above to complete Jettison Handle – Not Active until
Deployment Handled is pulled Jettison Handle is Electrically Interlocked
CONTROL PANEL
Fighter Class EnvironmentFighter Class Environment Similar approach to previous
however Large handles are not usually possible Replace with Buttons and
switches Toggle for Lock/Unlock Function Mash Button for Deploy Guarded Toggle for Parachute
Jettison Functionality remains largely the
same One exception, T-50 program had
room for Pull Handle configuration and preferred not to integrate the other approach. Integrated Pull Handles and
controls into the mounting position for an MFD
Lightning II DesignLightning II Design Same Electronics (Basically) –
Distributed Switch Design to Match Lightening II Cockpit environment and Pilot Desires
The Latter Always Being a Risk
Some Challenges in Switch Functionality and Environmental Testing are nearly behind us
Forward Lower Cost InitiativesForward Lower Cost Initiatives Current Business and VLJ Class
Aircraft use the Legacy Control Panel Specialized Switches, while very
functional have become Very Expensive
Internal BIT Processor has become obsolete – over 10 year old!
Still available but only in limited special builds
Internal Project to Upgrade and Update these issues May convert switch design to an
Airborne Internal Design
CONTROL PANEL
Control System Built In TestControl System Built In Test
Built In Test runs continuously and checks the following Current resistance of all pyrotechnic
circuits – a more precise test than simple continuity (as with test lights)
Checks input power voltage Checks Sequence time delay and
relays – at power on only ARM position feedback switches
Bit operates once per second, but requires failure is present for three straight occurrences before pilot report Reduces nuisance trips
Flight Mode reports data to pilot via control panel lights and repeater
Maintenance mode provides detailed results via laptop computer Allows quick isolation of problems
OPEN CIRCUIT - FSC1A (Deploy 1A)Fail/4 FSC2A ijs-off FSC1B ijs-off FSC1A ijs-off FSC2B ijs-off
Pass Pass Pass Pass Fail Pass Pass Pass
2.134 0.0 1.170 0.0 31.75 0.0 2.113 0.0
274
Fail/1 FTCA FMLA FSCR1A FSCR2A FSC1A FSC2A CALIBA ij's-off
Pass Pass Pass Pass Fail Pass Pass Pas
2.247 2.163 2.172 2.215 31.85 2.18 4.768 0.0
Additional EquipmentAdditional Equipment Aircraft Wiring
Experience and requirements are provided for every customer
TSP and termination locations are critical to EMI (read lightning) protection
Some customers prefer Irvin provide aircraft wiring harnesses
Installation Structure Provide adaptive structure to mount
equipment and transfer parachute loads into aircraft
Analysis and test also provided Thermal Protection
When required, thermal protection systems are provided for equipment
Parachute and mortar Deployed parachute riser APU compartment and exhaust Engine exhaust
MORTAR SYSTEM
ATTACH RELEASE MECHANISM
JSF Quadrapod StatusJSF Quadrapod Status
Working through Qualification of This Large Structure
Some Lessons Learned Related to Vibration Qualification and Metal Plating
Believe that these will be resolved shortly – we are not holding up the program
Will be well suited to help future customers
Ground Support Equipment (GSE) and Integrated TestingGround Support Equipment (GSE) and Integrated Testing
Integrated testing provided through Sophisticated Break Out Box
Allows failure insertion to assure BIT is functioning
Provides Pyro Device Simulation Mode Allows Simulated functioning of Control
System on aircraft Internal circuits limit current flow to
milliseconds, as with real pyro devices Internal device measures current
through each pyro path Allows review of delivered current and
deployment sequence
Current Re-design With Modern EquipmentCurrent Re-design With Modern Equipment
Desire to Reduce Weight, Size and Cost
Additional Customer Desire to Further Automate Testing Process
Customer/Airborne collaboration to produce new device
Another project slated for internal development this year
Will also update device based on recent lesson learned during aircraft installation More on this later
Manuals and ProceduresManuals and Procedures
Seemingly a simple issue, well developed manuals require significant effort
Installation Manual Includes initial and periodic
electrical tests – Functional Test Procedure
Operation Manual – pilot operations and emergency procedures
De-Installation Manual Many systems have been
damaged by mechanics assuming they know how to remove equipment
Well developed Acceptance Test Procedures
WARNINGEXPLOSIVE POWEREDPARACHUTE MORTAR
CLEARP/N: 756415
STAY
WARNING:
! !
BEFORE CONNECTING THE AIRCRAFT WIRING TO THE MORTAR CARTRIDGE, ESTABLISH A SAFETY ZONE AT THE REAR OF THE AIRCRAFT.
The switch settings must be as follows:
Key inserted in the Key lock
Key lock in the ‘LOCKED’ position
Deploy Switch Handle in the ‘UNLOCKED’ position
Contact Breakers (‘BUS A’ and ‘BUS B’) ‘pulled’
Lessons LearnedLessons Learned
System Approach to SSPRS This is critical to a successful high AOA program We continue to resist significant changes from what we believe is now
proven The Value of the System Provider and The Ability to Learn the
Lessons We were put into and remain in a unique position where we can learn
from the problems of the past We continue to learn from these issues Need to form closer ties with Military customers, where big organizations
and security serve to separate us from those lessons
Lessons LearnedLessons LearnedThe Evolution Since the ‘First System ApproachThe Evolution Since the ‘First System Approach’’
ARM Changes and Enhancements Servo Motor, Original Motor was too difficult to procure to support most
programs Lock witness switches, original design had an issue with simultaneity of
multiple arms in a single switch Fasteners, Original design incorporated commercial grade fasteners
Parachute and Mortar Parachute Riser, customer interaction during entire program allows
improved surveillance of installed equipment and enhanced designs for future installations
UV, Thermal and Moisture Protection Load Limit Fitting, a Fuse link type device that some customers request to
limit force that the parachute can apply to the aircraft After fielding one particular design, Irvin identified an unfavorable potential
loading condition Units were recalled and modified to protect against that condition
Lessons Learned - Control Panel ChangesLessons Learned - Control Panel Changes
Original Jettison Switch was not Spring Return Identified as a design discrepancy and corrected Original Units Retrofitted
Original Design required one fault to complete pilot declaration – BIT fault light is latched Experience has shown that ground plane voltage fluctuations can provide
occasional fault Algorithm changed to require three faults in a row before annunciation Significantly improved performance
Lessons Learned – Control Panel Changes (continued)Lessons Learned – Control Panel Changes (continued)
BFTC identified (post Global Express), that single internal switch failure (fails closed) could lock and deploy parachute Circuit modified such that two switch closures are required to complete deploy
command Retains most of quad-redundant architecture ability to deploy parachute Currently incorporated in all fielded systems
Aircraft Wiring, Original installations did not require wire twisting, shielding or specific termination location Result of lighting event described later Lessons learned now incorporated and recommended to all customers
Lessons Learned – Ground Test EquipmentLessons Learned – Ground Test Equipment
Original design used automotive class (Buss) fuses as pyro simulator We were frequent guests at Radio Shack or Auto Parts stores Choice between testing with fuse of lower current, or risking warm aircraft wire
Pyro’s require 4 amps for 10 msec to fire A 4 amp fuse will take 4 amps for minutes to hours
Developed current pyro simulator device, with current trace recording – far superior monitoring
Currently working on ‘Fool Proof’ system which will prevent accidental firing from improper connection
Operational Incidents – Lessons LearnedOperational Incidents – Lessons Learned
Global Express, Successful Recovery Locked in deep stall Yoke full forward for 10-20 seconds, no result Deploy parachute, recovery within seconds
Aware of some other events at commercial (business jet) customers, details to sketchy for discussion, however, recoveries have been completed high and low speed
F-16, flies Spin Systems even today Edwards Worldwide, we continue to provide new systems Has had operational incidents such as damaged connectors, program continues to
take appropriate corrective actions
Operational Incidents – Maintenance RelatedOperational Incidents – Maintenance RelatedLearning LessonsLearning Lessons
Have detected many real world failures Bad power, Open breakers, etc Poor ground connections in flight
Was a serious issue as this related to all pyros in the system – essentially the ground system was a single point failure
Connectors not properly connected Bent connector pins
More than one occurrence Ask my about my incident if we have time for questions !
Still suffer occasional hanger firing event Never with Irvin personnel present No injuries or significant equipment damage to date
Of course the spin system needs some work Always traced to not following procedures Working on a ‘fool proof’ system without disturbing excellent reliability of the flight
system
Lessons Learned – Recent SupportLessons Learned – Recent Support
Incident With Recent Pyro Vendor Devices were NOT Meeting Performance Specification Discovered During NASA Program Testing Failure Analysis Provides Sufficient Doubt about Reliability of Fielded Devices
Airborne Decides to Recall and Replace Fielded Devices
Hangar Deployment Event – During Our Installation Root Cause Traced to Lack of Ground in AC Supply Safety Advisory Issued to All Customers of this Equipment Future Designs Will Eliminate this Design ‘Feature’
Lessons Learned – Flight Test PlanningLessons Learned – Flight Test Planning
Consider the Planned Tests in the System design Balanced field length for taxi tests – What if parachute doesn’t deploy, do we have
runway to stop ? In-flight deployment, is this parachute force higher than emergency recovery ?
Image below is C-17 with reefed parachute to address that issue
Global Express In-Flight DeploymentGlobal Express In-Flight Deployment
T-50 Golden Eagle – Taxi Deployment TestT-50 Golden Eagle – Taxi Deployment Test
Courtesy KAI and ROKAF
T-50 Golden Eagle – In Flight DeploymentT-50 Golden Eagle – In Flight Deployment
Courtesy KAI and ROKAF
F-22 Raptor Taxi Test DeploymentF-22 Raptor Taxi Test Deployment
Courtesy Lockheed Martin