Embraer Phenom 100
Maintenance Airframe; Maintenance Powerplant
Workload; Troubleshooting; Training / Qualification; Situational Awareness; Time Pressure
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Manuals; Procedure; Staffing; Incorrect / Not Installed / Unavailable Part; Human Factors; Equipment / Tooling; Aircraft
Prior Maintenance Planning had been done to schedule the aircraft as 'Out of Service' for Maintenance for Standby Pitot/Static probe restoration (cleaning); Standby Instrument Functional Check; & Transponder functional check. Work to be performed would be under our 145 repair station by a trained tech. Due to scheduling conflicts; it was determined earlier in the week that only one of the two techs certified to perform the work and allowed to work this aircraft via company policy would be on site to perform. Two other 145 certified techs; not able to work the aircraft due to company policy; were on site all day and able to provide advisement and inspection of work performed; one of which was present during the incident and first noticed the issue in real time. I had reviewed the work pack for the original intended scheduled maintenance earlier in the week to ensure familiarity and look for any potential pitfalls or denotation of tools/procedures required that we may have missed in the initial planning and creation of the work pack. I was advised by management to revise the work pack to include ADC functional checks and restoration of the primary pitot sources. The work pack would then reflect all Ch. 34 items on the 24 month inspection time limit in the 91.411 & 91.413. Prior to the revision; the 91.411 ADC Check and 91.413 transponder checks had been split by roughly 365 days due to equipment changes and re-certification in the past. Performing the ADC checks despite not being due would realign all of the 91.411 & 91.413 related tasks together to all come due at the same time in the future. I updated the work pack on our computerized labor system; task tracking; and billing system; revised the billing as advised; printed out the additional applicable Aircraft Maintenance Manual tasks that were being added and compiled them with the previously printed and organized work pack binder. I also reviewed the tasks to re-familiarize and search for pitfalls/any issues I may have ran into the next day. Between the work pack update as described above and phone calls regarding other aircraft on our certificate with Admin work needing to be handled; I found myself leaving work finally as noted above.The first half of the work day I accomplished both Pitot Probe Restoration tasks per IAW the AMM instruction despite numerous delays from possible aircraft hangar movement requirements; maintenance labor/work order program tech issues that had to be resolved by the provider company tech support; and tool fashioning requirements that I was not able to predict despite prior preparations. The pitot lines for Embraer have different securing features than typical corporate/GA AN-fitting style line connections. This was not seen in the manual references for the tasks being accomplished. After a very brief lunch; I started back on the aircraft; continuing to deal with delays related to retrieving AN fitting adapters and setup for a P/S test and transponder test immediately after. After a parts run to the local hydraulic store for an oddball fitting required for the Standby Pitot/Static probe adapter that we were unaware of prior to the day we did not have any more of; It was afternoon and I was finishing final setup and preparations. I followed the Embraer AMM for the EMB500; in reference to our S/N aircraft; and made noticed it did not call for pulling the pitot/static heater breakers as a safety precaution. From experience with other aircraft of multiple manufacturers when dealing with pitot/static related tasks; I pulled the all heater breakers in the cockpit of the aircraft to disable the system. Once I applied power; and allowed for stabilization of the Standby and both PFD's; I set the pitot/static test box to 1500 ft altitude and 100 knots airspeed with a 1500 ft/min vertical speed as a preliminary check before committing to higher altitude for a leak check of the full system. It was at about 1000 ft altitude on the test box; while I was in the cockpit monitoring the PFD's and standby readout to follow the pitot/static tester handheld readout; that my coworker/inspector for this event yelled from outside the aircraft that we had smoke. I jumped out to identify the source and we saw the pilot side Pitot Probe adapter starting to ooze out the inside plastics from the heat. [The technician] immediately jumped into the cockpit as I told the tester handheld to go to ground so we could disconnect without damaged the aircraft systems. The altitude came down quickly; I yelled for [the technician] to shut down the aircraft power and we grabbed rags to pull the pitot adapters off while the plastics were still liquid; we promptly cleaned off the molten contaminants so it would not dry on the probes. Note- the aircraft was weight on wheels and knew it was on the ground. After everything cooled we inspected the adapters and found they would need replacement insides that can be ordered as kits. We also found some contaminants on the pilot side pitot tube had seeped through the drain hole. I broke up the solidified contaminants and performed the Pitot Tube Restoration task again; verifying the pitot tube was serviceable. Upon discussing the incident with our Director of Maintenance not long after; we were informed that Embraer's will in fact turn on Pitot Heat if certain breakers in the cockpit are pulled. We later found at the top of the AMM task for the ADC Functional Check I was performing; that Embraer lists AAM Task 34-10-00-480-801-A/200 'Pitot/Static Tester Connection' in the references section; however; in the set up and order of operations I followed up until the part where instructed to take the aircraft to altitude with the test box; it does not mention to reference this task like it does other tasks for preparing a safe aircraft for the following maintenance. The task also does not explicitly mention or have any warnings regarding leaving any heater breakers closed/opening them. We acquired another set of adapters and leak checked the pitot system for both ADC's and the standby; with the Test Box; due to the connection lines being opened earlier in the day for the Pitot Restoration tasks and the system showed leak free and functional. At this point I was able to sign off the work performed and RTS the aircraft for it to make its departure the next morning without delay. We experienced no delay in flight operations; however; very likely could have missed the next day flight if we couldn't resource other pitot adapters that fit properly; or even if we have damaged the pitot tubes in some way that the AMM would advise replacement.Embraer [should consider an] update to the AMM Task 34-15-00-720-801-A to include the referenced Pitot/Static Tester - connection task in the setup steps before applying pitot/static pressures to the aircraft to ensure safe configuration. Many pull breakers as additional safeties when performing work just in case other systems fail. A 'WARNING' note would be helpful as well; stating that improper pitot/static heat breaker configuration could potentially cause damage to equipment/the aircraft/personnel. I believe this would be an important update to have for the task because I'm sure this is not the first time someone with a lack of experience personally; with Embraer aircraft; has made this mistake; to ensure safety. Also; on our department's end; we will have to shoot for more realistic time allotments for work; planning; and setups. Also ensuring the proper training for each airframe and available hands to work the project will come into play. Without my coworker being able to double as my inspector; despite company policy deeming he does not under normal circumstances work on this aircraft; this could have been much worse. With ever changing schedules and customer needs; we all strive to do the best we can; but we will have to do better with recognizing the limits of safe operation schedules.
EMB-500 Maintenance Technician reported the test connections melted on the pitot probes while testing the pitot/static system.