Does your axle or tripod jack still support the amount of weight necessary? The best way to ensure the safety of aircraft jacks is by conducting regular proof load testing. Despite the critical role hydraulic jacks play in an aircraft maintenance facility, a number of aircraft maintenance professionals are unaware that aircraft jacks require regular maintenance. We will cover:
- Aircraft Jack Proof Load Testing Impact on Safety Assurance Systems
- Causes of Aircraft Jack Load Deterioration
- Maintenance & Testing Best Practices
- Onsite Aircraft Jack Load Testing
- How to Choose Onsite or Offsite Testing
Proof Load Testing Overview
Proof load testing is a process by which the fitness of the load bearing structure is tested to ensure it will maintain structural integrity during normal use. Proof load testing ensures the jack is able to perform in accordance with manufacturer guidelines.
Proof Load Testing Regulations
Regular aircraft jack proof load testing is highly recommended by most aircraft jack manufacturers. For example, Tronair recommends proof load testing on an annual basis. According to FAA regulations, MROs and FBOs must ensure that measuring tools and equipment are regularly tested. Jack proof load testing is another term for aircraft jack calibration. Since manufacturers recommend regular aircraft jack proof load testing, FAA auditors will check if MROs and FBOs comply. The FAA states that Part 145 repair stations should follow manufacturer documented maintenance and testing schedules.
In accordance with Safety Management System regulations, Part 145 repair stations should identify hazards and safety risks and assure the effectiveness of safety risk controls. A faulty jack can create safety risks. Aircraft jack proof load testing ensures jack reliability. These regulations have a noticeable overlap with Quality Control and Safety Assurance Systems.
Hydraulic Jack Failure Causes
Without proof load testing, there is no way for AMTs to know if a jack is reliable until it is too late. There are many factors that can impact the performance of your jack, but the most
common issues occur with the hydraulic system. For example, a seal can go bad that causes the hydraulic fluid to leak. This situation can lead to under performance or complete failure of the jack. This is why aircraft jack maintenance plans include inspection of the hydraulic system.
Outside of issues with hydraulics, structural damage can cause equipment to lose integrity. Structural damage can occur from mishandling, damage, or years of wear. For example, a dented leg on a tripod jack could easily collapse when being used to lift a plane. The structural weakness could result in physical harm to maintenance crew members or damage to the jack and lifted aircraft.
Proof Load Testing Benefits
Proof load testing verifies that the exterior and interior components of the jack comply with specifications of the manufacturer to reduce the risk of equipment failure. Regular proof load testing can meet required internal or external quality compliance mandates. Practicing regular jack maintenance and testing increases your value as a high quality provider of aircraft maintenance services. Aviation maintenance facilities may be required, by contract, to provide proof of annual aircraft jack proof load testing in addition to other quality measures. Incorporating manufacturer recommended preventative maintenance and proof load testing can augment your internal quality assurance program and enhance customer peace of mind.
Proof Load Testing Benefits
- Meet internal quality control systems
- Enhance internal Safety Management Systems
- Meet or exceed FAA safety and quality regulations
- Confidence in staff of equipment reliability
- Prolonged life of aircraft jacks
- Quality and safety procedures communicate value to customers
Aircraft Jack Recommended Maintenance & Testing Schedule
Manufacturers recommend 90 day maintenance and annual proof load testing. Testing may be advised outside of the regular schedule if the jack incurs damage. Common causes that require special testing include damage to the structure or the hydraulic system. Maintenance and proof load testing procedures differ by jack type and size. Axle jacks require different maintenance than tripod jacks, for example.
90 Day Preventative Maintenance
- Check hydraulic system for leaks
- Check jack structure for corrosion, excessive wear, bending
- Check fluid levels while rams are fully retracted
- Extend rams to check for leaks around seal, corrosion, or excessive wear
- Check paint condition, paint over any exposed areas
- Actuate hand pump a raise ram to full extension
- Apply water repellent that is Buna N compatible to rams on tripod jacks
- Open release valve and verify full ram retraction
- Lubricate casters, if applicable
The 90 day schedule can be completed in house if the technician has been trained. A third party can be used to satisfy certification needs or compliance regulations.
Annual Proof Load testing
- 105 – 110% capacity test
- Inspect hydraulic fluid for contamination, drain and flush if necessary
- *Includes all steps in 90 day schedule
How to Choose Onsite or Offsite Jack Proof Load Testing
Aircraft jack proof load testing can occur onsite, at a calibration laboratory, or at the manufacturer. Each option has benefits and drawbacks. MROs and FBOs must consider downtime, shipping costs, and convenience. Make sure you choose the best option for your organization.
Jack Prep Time
The time and labor involved in scheduling shipment, prepping for shipment, and putting the jack back into rotation upon testing completion is arduous. Shipping personnel often find that they must construct special crates to ship the aircraft jacks. The hydraulic fluid must be drained before shipping, which can require additional prep time from technicians or shipping personnel. From beginning to end, the process can take hours to days.
Shipping Process for an Axle Jack:
- Arrange a UPS pickup; plan this at least a day in advance (10 minutes)
- Drain all the hydraulic liquid – UPS does not allow aircraft jack shipment if fluid is not drained (30 minutes)
- Pack aircraft jack into a crate or box for shipping including necessary protective packaging materials (10 minutes)
- Weigh and measure the crate (15 minutes)
- Print shipping label and attach to the crate (5 minutes)
- Stage package for UPS pickup (5 minutes)
- Upon return of aircraft jack, unpack crate (5 minutes)
- Refill jack with hydraulic liquid (30 minutes)
That is a total of 1 hour and 50 minutes spent on shipping/receiving the jack; and that’s assuming everything goes smoothly. Also consider that this time investment is for a single axle jack. Most aircraft maintenance facilities will have about a dozen axle jacks, meaning three days of labor will go towards managing the process.
Shipping Process for a Tripod Jack
- Drain all the hydraulic liquid (30 minutes)
- Get the overall weight and size dimensions of your jack (20 minutes)
- Go online or call to get a freight quote and schedule pick up; schedule this a day or two in advance (25 minutes)
- Secure the jack to the pallet for shipping, ensure any additional carrier packing requirements are met (40 minutes)
- Ensure proper labeling is completed per your carriers request and that a bill of lading has been completed (20 minutes)
- Stage package for freight carrier pickup (5 minutes)
- Upon return of aircraft jack, unpack pallet (20 minutes)
- Refill jack with hydraulic liquid (30 minutes)
This is a total time of about 190 minutes (a little over three hours) spent on shipping and receiving for one jack. Again, most facilities will have a minimum of a dozen tripod jacks. This means that you’re losing nearly a week of labor every year managing the process. Considering all of the above, onsite aircraft jack proof load testing can save you a significant amount of time and hassle. This negates time wasted on shipping and receiving activities.
All you need to do is call an onsite calibration service provider, answer a few questions, and schedule a day for onsite service. The whole conversation may take 30 minutes at the very most (and this could be for service on every jack you own). When they get to your location, the calibration technicians will take care of any fluid handling involved. Onsite calibration service eliminates additional such as scheduling, shipping, and packing/unpacking.
Proof Load Test Costs
Many manufacturers charge a testing fee that is likely 25-30% higher than independent calibration service providers. While the fees are not astronomical, this cost adds up. Facilities with three or more jacks will notice a sizable increase in rates. A third party testing facility can provide the same level of quality testing and typically charges 25-30% less than the manufacturer whether the jack is being shipped to the third party or tested onsite.
Hydraulic jacks are expensive to ship due to their size, weight, and the cost of freight. The cost of shipping will vary depending on factors such as distance, jack type, and shipping service provider. In our experience, many companies wind up expediting shipping to reduce down time which can further add to the price. For companies who have multiple jacks that require testing, this can make shipping difficult. Most tripod jacks must ship via freight carrier and require significant effort to crate or otherwise prepare the jack for shipment.
You must consider the length of the entire process. You will be without the jack during shipping, testing, any necessary repairs, and return shipping. This process can leave your facility without one of your most vital maintenance tools for months. The average time for freight shipment on a tripod jack is one week in each direction. The average turnaround time for testing is one week. This leaves you without your tripod jack for a minimum of three weeks! If you’re shipping an axle jack out for testing, the shipping time may be a day or two shorter. Either way, equipment will not be available at the hangar for a few weeks. When using a slower than average manufacturer or provider it can take even longer.
If you choose to utilize an onsite testing provider, testing can be done in about 30 minutes per jack. Small adjustments or repairs can be made on site. If the jack fails testing and requires larger repairs off-site, the time turnaround time is lengthened. If the jack is deemed past the point of repair, it may need to be replaced. Time out of service would be equivalent to order and shipping time for a new aircraft jack.
If you opt for onsite proof load testing you will not have to deal with excessive shipping costs, but you will need to pay for certain aspects of calibration technician travel. In most cases, the travel costs for the technician will be considerably lower than the cost to ship your jack to an external calibration facility. While there are some very attractive savings for onsite testing services, you must
carefully consider the cost of technician travel before you make your decision. These costs can be highly variable.
Consider an MRO in New Jersey and an onsite testing provider from Ohio. The technicians would typically drive to the location. In this case, travel costs would include fuel, hotel, and per diem costs for each technician. Scheduling would be easier, as travel doesn’t rely on flight times. If this is the case, you stand to benefit significantly with onsite aircraft jack proof load testing services.
If a facility is located in California and you were still using an Ohio based service provider, costs and planning get a bit more complex. Travel costs would include the cost of the flight, rental car, hotel, per diem, and shipping of the proof load testing fixture (if applicable). If this is your situation, consider the number of jacks you have that need attention. If you only have one or two jacks, this may not be the best option for you. But if you have a larger number, you may still find onsite testing to be the most cost effective way to go. This does not include considerations for turnaround time on aircraft jack proof load testing and convenience. If an FBO has ten jacks, testing can be completed in one day with onsite aircraft proof load testing.
Aircraft Jack Proof Load Testing Summary
Following 90 day maintenance schedules and annual aircraft jack proof load testing can improve hangar safety and lengthen useful life of equipment. Adhering to manufacturer recommendations enables MROs and FBOs to meet or exceed internal quality and safety requirements, comply with FAA guidelines, and uphold military contract stipulations. In most cases, having a service technician onsite is much more cost effective and enables you to do what you do best – maintain your aircraft with confidence to ensure the safety of the passengers and crew.
e2b calibration is one of the few ISO/IEC 17025 accredited calibration and repair laboratories in North America providing onsite jack stand proof load testing services. We have made a considerable investment in the design and production of a proprietary proof load testing fixture. This allows us to conduct onsite calibration and testing services at a fraction of the cost of other providers.
About e2b calibration
Located in Northeast Ohio, e2b calibration (www.e2bcal.com) provides onsite proof load testing for aircraft tripod jacks (both single-stage and multi-stage) and axle jacks with a capacity up to 75,000 pounds. We can service a broad range of manufacturers including Tronair, Malabar, Langa, Columbus, Dedienne, Meyer, GB Barberi, Hyro Systems, JSM AG, Wag-Aero, and more.
Our customers include leading aircraft maintenance facilities including Delta, Cape Air, Constant Aviation, Flight Options and other FAA-regulated maintenance facilities for commercial airlines, charter services, private and fractional jet businesses, and cargo air service providers.
As an ISO 17025 accredited test equipment calibration and repair laboratory traceable to NIST and ANAB accredited, e2b calibration provides turnkey calibration and repair services for most IFR (instrument flight rules) aviation and avionics equipment including air data test sets, pitot static systems, traffic control avoidance systems (TCAS), aircraft scales, and other maintenance equipment such as crimpers, multi meters, flow meters, and test equipment for pressure, torque, and electronics.