Date: 201406
Local time of day: 1201-1800
Aircraft: B737-300
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch; Climb
Aircraft component: Interphone System
Component problem: Design
Reporter organization: Air Carrier
Human factors: Situational Awareness; Workload; Communication Breakdown; Confusion; Distraction
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew FLC complied w / Automation / Advisory; Flight Crew Became Reoriented
Contributing factors: Human Factors; Aircraft; Procedure
Primary problem: Ambiguous

Narrative: I am writing because I am curious as to whether the lack of a fully functional intercom in the -300 aircraft has been looked at in terms of safety of flight. I think we all can agree that over the last two decades flight deck communications has been an area of focus. Checklist discipline; briefings; and QRH procedures have all resulted in an increase in verbal communication on the flight deck. Today we are continuing to add to the necessity for clear communication during complex procedures such as RNAV Climb Via and Descend Via SIDs and STARs. Further; international flying into regions where English is not widely spoken and it is more important than ever to be able to clearly hear and understand Air Traffic Control. (Communicating in Mexico is a lot like trying to talk to someone using a tin can and a string!) Finally; during a non-normal [situation]; it is imperative that the flight deck Crew be able to communicate clearly when reading and responding to the QRH. Miscommunication here could result in a bad situation becoming much worse. While flying a -300 over the last two days; in VFR weather no less; I noticed that there were a lot more missed communications between the Captain and myself. I found myself asking him to repeat himself often. Even ATC communications were compromised since we were operating with one ear piece moved away from an ear so that we could talk and hear one another. I want to share an example with you. I made a typical 'new guy' mistake today. I loaded the entire route into the FMS but failed to ACTIVATE and then EXECUTE the route. We took off; thankfully on a radar vectored departure and not an RNAV departure; and while still on vectors I selected VNAV. It would not engage but rather we got a 'check altitude' message in the scratch pad. I was confused to say the least. 'The VNAV won't engage;' I said. The Captain responded; 'OK.'   He thought I was telling him that I was engaging the VNAV but due to the noise level he misunderstood. Right about that time; we were cleared to the first fix on the flight plan. LNAV would not engage either.  (The Execute button did not light up either.) We struggled to communicate while talking about what was happening in the climb; looking up the VOR frequency (made much easier thanks to the iPad); and turning the airplane toward the VOR. To say that we had gone from Yellow to Red would be accurate. And; this was on a clear; VFR day in a low traffic area. True; the source of the problem was my failure to properly program the FMS and the Captain's failure to catch it but it was exacerbated by it. If the -300s will remain in the fleet; I think that we should consider the value of installing an intercom in those aircraft to allow clear communication during normal and non-normal operations.




Synopsis: A B737-300 pilot described the difficulty communicating using that aging flight station intercom/communication system which actually hampers pilot to pilot and ATC interaction.