EMB 170 flight crew reported an electrical malfunction during takeoff which resulted in two rejected takeoffs and a return to the gate on a training flight. The flight departed after maintenance deferred the generator drive unit.
Synopsis
EMB 170 flight crew reported an electrical malfunction during takeoff which resulted in two rejected takeoffs and a return to the gate on a training flight. The flight departed after maintenance deferred the generator drive unit.
Narrative
CA qualified upgrade IOE. I was pilot flying operating in the left seat and the check airman was pilot monitoring in the right seat. The events leading up to the takeoff were uneventful. We departed the gate prior to the Tower opening; early in the morning. Due to the Tower closure; the short taxi; and it still being dark outside; I opted to start both engines after the pushback. We ran the appropriate checklists and held short of Runway XXL (which was NOTAM closed). As we were holding short; Tower opened and cleared us to cross Runway XXL. Subsequently; they cleared us for departure off Runway XXR; and on course to FL270.I set takeoff power; and we did our check thrust/thrust checked" callouts. We received an amber "IDG (Integrated Drive Generator) 1 OFF BUS" caution message around 50-60 knots. I called to reject the takeoff and performed the rejected takeoff procedure. The max speed I saw on the PFD (Primary Flight Display) was just under 70 knots before trending downwards. We notified ATC and taxied off the runway onto the crossing runway as instructed by Tower. We made a PA to the flight attendants and passengers to remain seated. We then followed ATC instructions and taxied back to hold short of Runway XXR on Taxiway 1. No assistance was required or requested from ATC. Once holding short; we accomplished the 'IDG 1 OFF BUS' QRH checklist. This had us turn the IDG 1 from AUTO to OFF; then back to AUTO. This cleared the message immediately. There were no further actions listed in the QRH procedure once the message had cleared. Following this we reviewed the MFD(Multi-function Flight Display) electrical synoptic page to confirm the IDG had taken the electrical load; which it had. I asked the check airman to display the MFD status page on his side to confirm the brake temperatures were still in range for another takeoff. I spoke to the flight attendants and then to the passengers to notify them of the situation and that we would be departing again shortly. We re-ran the taxi checklist and the before takeoff checklist in their entirety before notifying ATC that we were ready for departure on Runway XXR again.Once cleared for takeoff on Runway XXR for the second time; we lined up and I set takeoff thrust. As I set takeoff thrust; I noticed some exterior lights flickered; and almost immediately afterwards we lost display units 1 and 4 and received numerous caution and warning messages on the EICAS. I rejected the takeoff immediately at around 30-40 knots; just after setting the thrust; and the check airman notified ATC once again. As I slowed the aircraft; I noticed that we no longer had nosewheel steering. I brought the aircraft to a complete stop on the runway and set the parking brake. We notified ATC that we were unable to exit the runway. A PA was made to the passengers to remain seated. Because my MFD (display unit 2) reverted to a PFD display; I used the reversionary panel to manually change my display to the original MFD display. I checked the electrical synoptic page once again and saw that the entire left side of the electrical system was no longer powered (GEN 1; AC BUS 1; TRU (Transformer Rectifier Unit) 1; DC BUS 1). Various other readings on this display were abnormal; including an indicating dashed AC GPU with dashed values (with no AC GPU attached to the aircraft). The TRU 1 varied between 0 Amps and over 1000 Amps; far outside the normal operating range. The bars which show the connections between the electrical components did not connect to the left side of the system.We called the flight attendants to notify them of the situation. Due to the loss of half of the electrical system; they were under emergency lights in the cabin. We once again made a PA to the passengers informing them of the situation. I started the APU to attempt to restore power to that side of the electrical system. But; it did not successfully restore power to the system and would not tie into the AC BUS 1 /DC BUS 1 side. After furtherdiscussion with ATC; we attempted to call operations to get moved back to the gate. I was unable to reach operations on the published radio frequency or the phone number listed in the release. The check airman called Operations and subsequently Maintenance Control to notify them of the situation. I continued to discuss our possible actions with ATC. Following his phone call with Maintenance Control; the check airman made a Logbook entry describing the events and the abnormality. ATC was able to reach our operations and notified them to bring us a tug to move us off the runway. We made PA's to the passengers and kept them informed about the situation; as well as the flight attendants. As the tug approached; we notified ATC to inform the airport police; who was escorting the tug; that we would shut down both engines. Once the engines were shut down; the APU retained the electrical load that was previously under IDG #2. But it did not restore full electrical power. We were towed back into the gate and deplaned.We consulted with Maintenance Control and contract maintenance after returning to the gate. With Maintenance Control; contract maintenance; and coordination from the station; we ran the maintenance procedure to disconnect the IDG #1 by starting both engines; and did an operational check to ensure that IDG #2 and the APU could sufficiently handle the electrical system. It was a successful check and maintenance deferred the #1 IDG. Once maintenance was complete we re-boarded; refueled; and departed without any further incident.After landing in ZZZ1; we were notified that the correct procedure would have been to consult with Maintenance Control after the first rejected takeoff. A pilot debrief was completed for the rejected takeoffs within the requested 24 hour timeframe.I believe the initial action of rejecting the first takeoff for the caution message below 80 knots was correct; according to our AOM procedure. After review; the actions that followed were not complete and did not fully comply with company procedure. Following the rejected takeoff; I was focused on taxiing the aircraft clear of the runway; notifying the passengers and crew members of the situation; and then resolving the problem through the QRH procedure. I neglected to consider that our best action was to contact the company and Maintenance Control to get further assistance before proceeding. Neither myself or the check airman considered this action prior to attempting a second takeoff. The quickness of the resolution through the QRH procedure falsely led us to believe that the problem had been resolved.The cause of this event/non-compliance with company procedures was a lack of experience and understanding of procedures for this type of scenario.Suggestions: Slowing down; evaluating the situation in its entirety; and using all available resources. Having a better understanding of maintenance procedures off the gate; but still on the ground; could have prevented a second rejected takeoff with further electrical issues. Notifying Operations and Maintenance Control for a rejected takeoff and the generator off caution would have been wise before proceeding for another takeoff attempt."
Second reporter narrative
We were cleared for take off on Runway XXR from ZZZ I myself was the PIC of the flight conducting IOE on an upgrade student. The student was the Pilot flying for the flight. Upon lining up on Runway XXR; the pilot flying set take off thrust and made the appropriate call out of 'Check Thrust'. After I made the 'Thrust Checked' call we were passing 60 knots a master caution warning went off. Immediately looked at the EICAS and saw 'IDG (Integrated Drive Generator) 1 OFF BUS' I read out laud the EICAS message. The pilot flying initiated the rejected take off procedure. I as the pilot monitoring made the call to the Tower advising we were rejecting take off. We cleared the runway and stopped; I made a P.A advising everyone in the passenger cabin to remain seated. We taxied to the end of the runway and ran the IDG 1 off bus QRH procedure. The procedure had us reset the affected IDG. Once the affected IDG reset. both pilots verified the electrical system was fully working again and agreed that all systems were running normally and should depart again.Once we received our take off clearance for departure on Runway XXR for the second time; we lined up on the runway and the pilot flying sat the thrust levers in the take off position. Once the take off thrust was set. the everything in the flight deck went dark and emergency lights turned on; We decided once again reject the take off and stop on the runway. Company Standard Rejected Take off procedures were followed again and we stopped on the runway. Once we attempted to vacated the runway; The pilot flying saw that we didn't have any steering anymore. We saw the electrical status page and saw the aircraft was now running on Battery power only. We then started the APU to see if we can get the APU to take the electrical load but the APU didn't take any electrical load after the APU was started. We then coordinated with Maintenance Control and ZZZ Ops to get the aircraft towed back to the terminal where contract maintenance was awaiting for us to trouble shoot the issues.I now reflecting back on the events of this flight; I conclude for us as the crew that Maintenance Control should of been called after the first rejected take-off to receive better guidance on the IDG issues and perhaps avoid the second rejected take off.Cause: High stress work load during the Rejected take off while conducting IOE on an upgrade student. Concentrating that IOE student handled the rejected take off procedure correctly. Suggestions: Overcommunicate with company Operations/Maintenance Control even if it's not required by company procedures instead of under-communicating with Operations/Maintenance Control
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.