- 05 Jul 2019
- Dave Higdon
- Engines - Biz Av
Not knowing where your parts are coming from, or their previous history, can have a detrimental effect on the function of your jet. Andre Fodor provides anecdotes and insights into why you should be proactive over the replacement parts used in your aircraft…Back to Articles
Not knowing where your parts are coming from, or their previous history, can have a detrimental effect on the function of your jet. Andre Fodor provides anecdotes and insights into why you should be proactive over the replacement parts used in your aircraft…
At the call of ‘V1’, I swiftly rotated the jet into the air and was relieved that its first visit to the service center had ended without major incident. As the pilot monitoring called a positive rate and I requested gear up, however, it became acridly clear that my feelings of relief were premature.
Within seconds the cabin and cockpit were filling with a pungent thin smoky haze. We donned our smoke googles and oxygen masks, declared an emergency and landed within two minutes of take-off. The culprit, it emerged, was an improperly installed rubber seal inside the engine’s core. The solution required its removal and shipment to the factory for repair.
As the engine returned from the shop for re-installation, we reviewed the tear-down report and found that an 18,000-hour (17,000-cycle) refurbished fuel pump had been used to return our nearly new engine to service!
Our jet’s engine model was the same used on airline commuter fleets, whose priorities mostly concern returning an aircraft to service to make revenue. Corporate operators are completely different, so it is unacceptable to place a high-time part in a brand-new aircraft.
The above incident raises a question: what are some of the challenges of preserving the integrity of your aircraft, particularly in relation to parts replacement?
Replacement Parts: Never Assume
New owners and operators of business aircraft can be a little naïve regarding aircraft replacement parts. After all, we wouldn’t expect bad components to be replaced with anything other than a new part in our cars.
And, if an airplane is under warranty or enrolled on hourly maintenance programs, it’s a common assumption to make that replacement parts will be new, or at least aligned with the age of the aircraft.
The reality can be very different. Warranty and hourly maintenance programs may only guarantee a replacement part. So, unless you perform due diligence, taking a proactive role in choosing the best part in the stock pool, you may well end up with the first pick off the shelf with the quickest delivery time.
To return to the story of our engine fault, the OEM did not consider it to be unacceptable for our aircraft to become a ‘Frankenstein’s Monster’ of parts – i.e., a random collection of low-pedigree parts. It took a lot of discussion and the involvement of more senior management at the OEM for us to get our original part back after it was repaired.
Replacement Parts: Check the Repair Action History
Another flight department I was part of once operated six of the same jet type and experienced a high number of Flight Management System (FMS) display failures. Those FMS displays would go blank after several hours in flight.
Each jet had two units installed, and as we continuously replaced these screens once another one had failed, we began seeing our originally uninstalled serial number displays rotate back into the parts stock.
Reviewing the tear-down reports, we noticed the infamous No Fault Found (NFF) sign-off for those units. The result was essentially a merry-go-round of continuously failing displays that contaminated our fleet with low dispatchability.
The lesson is that it’s important to maintain a ‘zero acceptance’ policy within the flight department for failed parts that have no clear repair action history. NFF parts tend to be short-term bench checked whereas our failures were occurring over long operational times. NFF does not guarantee against failure after re-installation.
Replacement Parts: Living with the Best Exchange
Not long ago, I was asked by the buyer of an aircraft if they could negotiate a contract addendum for only new parts replacements. Although it’s a valid question, I explained that this would ultimately be fruitless as, often, either no new parts are available or would require weeks of downtime before the parts could be delivered.
The buyer then asked why they couldn’t have the original parts returned after they’d been repaired, utilizing an older replacement as a loaner in the meantime?
The reality is that parts providers would first have to agree on a re-stocking and rental fee, while also placing a hold on refund charges. Then someone would have to track the part’s serial number through the repair system, re-stocking and re-delivery.
Further – depending on the part – significant tear down, return to service time and expenses would be associated with this second exchange and the possibility of new maintenance issues developing from the additional maintenance would increase.
To summarize, it’s simply not practical. Ultimately, the trick is to choose the right replacement part and live with the best exchange.
The above examples should all serve to highlight that it’s vital to manage the parts replacement coming into your aircraft and know the costs. You should seek to preserve your ‘like-new’ aircraft status by not dropping the ball on parts procurement, while accepting you won’t get ‘new for old’.
Diligence is required, and you’ll need to take time to research and discuss which one is the best component replacement for your aircraft.
To do so, you will need to learn as much as possible about any prospective part to be installed on your aircraft, undertaking serial number research and, where necessary, doing some detective work. Replacement parts is simply not an area of aircraft maintenance that you can afford to be relaxed about.
Aircraft reliability is a combination of preventions and well-made decisions and it’s up to you, as flight department manager, to lead your team in making the best choices.