Energy Relief Seat Fitting for FAR 14 CFR Part 121
Introduction:
References:
The Purpose:
The Fitting Function:
On Seats Comparison:
How the Device works on the passenger seats?
Summary of the 16g test per Federal Register 14 CFR Part 121 sec 25.562:
How the 16g is Derived?
The Function of The New Seats Fittings:
How it works:
Ultimate Predetermined Impact Load of the New Seat Fitting:
It is Not Just Another Ordinary Seat Fitting:
Conclusion:
INTRODUCTION:
A new seat fitting is a step closer for airlines to comply with the FAR 14CFR 121 Final Rule. In 2002, airlines were balking at a US Federal Aviation Administration proposal to mandate installation of 16g seats on almost the entire US passenger jet fleet. The long-anticipated ruling was supposed to require airlines operating under Part 121 rules to retrofit their aircraft with 16g seats over the next 14 years. Manufacturers would need to install the new seats on all transport-category aircraft over a few years. At present, seats are required to meet the 16g impact specification only in aircraft type-certificated after 1988, such as the Boeing 777. The FAA’s proposed rule would cover all aircraft manufactured after 1958, which mostly have seats rated to withstand a 9g impact. Manufacturers and airlines have been aware for years that the 16g standard was an eventuality, but the Air Transport Association says the proposed ruling “will be difficult” to meet because of the cost to retrofit aircraft with the new 16g seats.
A business plan has been established to seek for a suitable investor to market the new generation seat fittings meant for the 16g seats ruling and for the replacement of the current conventional fittings of those older aircraft with 9g compliance seat and for airplane built before 27 October 2009. This new generation fitting is designed to secure seats with at least a 9g requirement to retain onto the floor track beyond 16g dynamic pulse. The fitting has a new innovative device built-in to relief a predetermined crash energy equivalent to not less than 16g impact primarily meant to meet the Final Rule. The award winning invention, the impact-energy dissipation device has been the heart of the new technology. The chosen launch market in the 16g passenger seat segment.
References:
- Biz Plan,
- IEDD Test Video,
- Patent reference,
- Federal Register CFR Part 121, FAA requires safer seats
- The Seattle Times Report,
- CAA Paper 2005/03 DOT/FAA/AR-04/27
The Purpose:
1. To meet the FAR 14 CFR 121 Final Rule for16g seat requirement;
2. To prevent seat from dislodgement even beyond twice the amount of g force;
3. To reduce seat weight.
The fitting function:
- prevent aircraft passenger seats from being detachment from its seat-tracks to increase the survivability of passengers in case of a crash;
- isolate impact energy from the crashworthy structures that may be transmitted onto the floorboard of the aircraft;
- allow lighter seat to achieve the 16g requirements;
- allow the use of conventional seat-tracks (existing) for 16g compliance seats.
ON SEATS COMPARISON:
REPLACES THIS REAR SEAT FITTING
A typical passenger seat is shown with the rear fitting. The new device remains the same as the normal fittings and do not change the Pitch and Roll relief criteria as per the AC25-562 and it also meets the seat deformation limit and egress paths as per the TSO-C127.
The new fitting is meant for relieving the impact energy from the forward pulse to prevent the seat from breaking off from it seat-tracks with its predetermined impact load beyond the current 9 or 16g requirement.
THE ORIGINAL FRONT STUD
The front studs may be retained or reworked depending on the original seat configuration.
Summary of 16g Test per Federal Register 14 CFR Part 121 sec 25.562:
What is a 16g seat?
For transport category airplanes, a 16g seat is one that meets the 9g requirements of Sec. 25.561 and the [[Page 56544]]dynamic requirements of Sec. 25.562. A 16g seat is tested in a manner that simulates the loads that could be expected in an impact-survivable accident. Two separate dynamic tests are conducted to simulate two different accident scenarios: one in which the forces are predominantly in the vertical downward direction and one in which the forces are predominantly in the longitudinal forward direction. The highest load factor is in the forward direction at 16 g’s. This is why these seats are commonly referred to as 16g seats. The test procedure requires “crash testing” the seat (i.e., rapidly decelerating the seat in accordance with the criteria in Sec .25.562(b)). For the 16g test, this means deceleration must go from a minimum of 44ft/sec to 0 ft/sec in not more than 0.09 seconds with a peak deceleration of at least 16g’s. The seats are tested with seat floor tracks that are representative of those that will be used in the airplane installation.
How the 16g is derived:
Test Requirement is 44 ft/sec over 0.09sec impact:
P = mf
= [Seat Gross Weight/g] x [v-u/t],
= [Seat Gross Weight/g] x 489,
P/ [Seat Gross Weight] = number of g
Therefore:
[Seat Gross Weight/g] x 489 / [Seat Gloss Weight] = 15.28g (16g requirement)
The Function of The New Seats Fittings:
- The new seat fitting is design to dissipate at least a 16g load to prevent detachment from its seat track;
- The impact load is dissipated in a control fashion to limit the pulse or to allow a safe level of load to transmit onto both the seats and the floor tracks.
How it Works:
- A predetermined ultimate load is selected not more than the seat limit load, but is not limited to suit desire requirements.
- At impact the seat remains restrained up to its designed static restrain load before the device is activated; the device activates only when impact load exceeded the designed static restrain load.
- Should the crash exceeds the device designed load, which is calibrated beyond the 16g, the excess energy will then be borne by the conventional seat assembly . This will however protects the seat from detachment within the 16g restrain ability.
Ultimate Predetermined Impact Load of the New Seat Fitting:
The device is adaptable to the desire relief load. The total relief load includes the inertial 9g static load of the gloss seat weight plus the additional relief load, the device bears a total of not less than the 16g load.
THE ABOVE TABLE SHOWS SOME OF THE PRELIMINARY RESULTS OF THE DYNAMIC TESTS WITH AND WITHOUT THE DEVICE.
It is Not Just another Ordinary Seat Fitting:
- This innovative fitting allows the seat to hold onto its seat tracks beyond the required 16g requirement.
- This revolutionary seat fitting will not dislodged when crashing within a very high predetermined impact speed; even without any additional structural enhancement on the 9g compliance seats is required.
- The inventive device isolates the destructive forces from the seats mounting and does not transmit the crash load beyond the fitting to protect its floorboard from buckling, thus prevents catastrophic structural failure within the airplane.
Conclusion:
This Innovative Solution is expected to attract many interested airline operators and airplane owners; this innovative design is revolutionary and will save Millions of Dollars from retrofitting should they be needed to compliance with the FAR 14 CER Rart 121 Final Rule.
Please go to http://seatfitting16g.wordpress.com/the-award-winning-invention-the-impact-energy-dissipation-device/ for video demonstrations.
By Lawrence CWN Chong,
Aerodraft Innovations
Contact us: cwnchong@aerodraft.com
